SuzukiSavage.com /cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Beefing up the Clutch /cgi-bin/YaBB.pl?num=1615547049 Message started by DragBikeMike on 03/12/21 at 03:04:09

Title: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:04:09 If you keep souping up your engine, eventually you will find a weak link.  In my case, the first weak link was the clutch.  In my never-ending search for power, the clutch started to slip.  Thankfully, nothing was damaged. A quick inspection revealed that all the clutch components were in factory-new condition.  All the fiber and steel plates were in spec, and there was zero evidence of overheating.  The springs had the same force as they did at 1000 miles, and their free-length was in spec.  The release system was adjusted properly and there was adequate free-play.  The poor little clutch just couldn’t hold the power. The immediate fix for my slipping clutch was to install a Barnett clutch kit.  The Barnett kit fixed the problem, but it did so by using springs that are about 13% stiffer than stock.  Those stiffer springs increase stress in the release mechanism.   I would prefer a solution that does not increase stress in a failure-prone component. It was time to take a hard look at the Savage clutch.  What can be done to beef up this weak link?

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:06:00 I’ve seen several reports on this forum pertaining to failed clutch release cams.  Like this one from MMRanch.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:07:20 When the release cam fails, the damage won’t necessarily be confined to the cam itself.  The cam fails, falls apart, and proceeds to wreck up other stuff.  Like this release plate.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:07:58 It could be a lot worse.  There are all sorts of gears, chains, sprockets, bearings and other doodads that the rock-hard metal fragments can play hell with.  So right up front, any improvements to the clutch assembly must take into consideration the release cam.  Anything that increases stress on the release cam must be avoided. The plan was to try to beef up the clutch without using stiffer springs.  If that couldn’t be achieved, then figure out the safest way to use stiffer springs.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:08:49 The stock Savage clutch is a typical motorcycle wet clutch.  It uses a total of eleven plates (six fiber drive plates and five steel driven plates).  There are four coil springs that clamp all the plates together and lock up the clutch.  In general, there are three ways to increase the torque limit on the clutch. Increase the clamping force (i.e., stiffer springs) Increase the coefficient of friction (i.e., change the friction material) Increase the surface area of the friction material (i.e., more plates, larger plates, etc.)

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:10:05 It is easy to increase the spring force.  A set of Barnett springs or early DR650 springs will do the job.  But with heavier springs, the release cam is going to be subjected to more stress every time you pull in the clutch lever.  For now, that option was off the table.   Increasing the coefficient of friction might be as easy as switching to the Barnett plates, or possibly EBC plates.  I could test that by opening the clutch cover and swapping out the Barnett springs with stock springs.  Problem is, I don’t know anything about the coefficient of those aftermarket plates.  It might be higher.  It might be lower.  It might be the same.  I guess it would be reasonable to assume that if I ran the Barnett plates with stock springs, and if it didn’t slip, then the friction characteristics of the Barnett material must be better (in this case a higher coefficient). Increasing the surface area of the friction material is complicated, a lot more complicated.  Naturally, I chose that approach.  Hey, it’s complicated.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:10:54 I have seen ideas posted on the forum regarding clutch mods.  The addition of another friction plate, adding a steel plate, sanding down plates to allow room for an extra plate, replacing the special outer friction plate with a standard friction plate, eliminating the wave washer, shimming springs, stiffer springs…..  Did I miss any? We have this crazy powdered-metal release cam that breaks unexpectedly.  Get the geometry a little out of whack and you end up with a snapped release cam.  It’s usually a long walk home.  Any modifications must consider the release cam. I initially figured that the broken release cams were the result of coil-bind and/or poor clutch pushrod setup.  After a closer look, I think there might be a little more to it.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:12:33 This shows three clutch springs, a stock spring on the right, an early DR650 spring in the center, and a Barnett spring on the left.  The DR spring coil-binds at 22mm.  The stock spring coil-binds at 19mm.  The Barnett spring coil-binds at 17mm.  On a stock clutch, the installed spring height is 26mm.  Using these values, you can figure out available travel.  Available travel is 4mm with DR springs, 7mm with stock springs, and 9mm with Barnett springs.  That’s a huge variation.  Be careful with springs.  Put in the wrong springs, or reduce the installed height too much, and you might set up coil bind.  Coil bind can result in a broken release cam.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:13:54 The release mechanism has a 7:1 ratio, meaning for every 7mm that the lever arm travels the release cam pushes the pushrod 1mm.  I checked the release travel several ways to get an idea how much the clutch springs would be compressed when the lever on the handlebars was pulled all the way in.   First adjust the clutch cable to remove all the slack.  Then loosen all the clutch cover bolts.  Then pull the clutch lever on the handlebars all the way in and lock it in place.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:15:11 Lightly tighten all the clutch cover bolts (finger tight only).  Adjust the bolts until the gap between the cover and the gasket is uniform all the way around.  Then measure the gap with a feeler gage.  It’s 1.8mm (.070”).  That’s how much the release cam can move the clutch release plate, which is how much the springs will be compressed.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:16:41 I double checked the release travel with the clutch cover removed.  When the release lever was moved ½” (12.7mm), the release cam pushed a dial indicator .065” (1.65mm).  Pretty close.  I think we have that piece of data nailed down.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:18:16 Let’s look at some of the things that affect the pressure disk travel.  This is the pressure disk.  It’s the part that the springs act on to squeeze all the plates together.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:19:43 If you assemble the clutch with a couple of light springs, you can cycle the pressure disk with your fingers.  It makes it easy to check a few things.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:21:46 On the stock clutch assembly, there is .243” clearance between the inner-most friction plate and the bottom of the clutch basket slot.  I call it the “bottom plate gap”.  Note how the edge of the hub flange is flush with the outer edge of the basket.  The hub rotates but it does not move in & out.  It’s position is fixed on the transmission input shaft.  Throw in some extra plates and the only component that will change position is the pressure disk.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:23:41 When I push in on the spring bolts, I can move the pressure disk inward until it hits the stops in the clutch basket.  Then I can use feeler gages to measure how much it moved.  On the stock clutch, the pressure disk moves about .157” (4mm).  That’s well shy of coil bind, and way more than the available release mechanism travel.  Nothing will interfere with clutch operation.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:25:21 With stock components, available pressure disk travel is 4mm and the release mechanism travel is only 1.8mm.  That leaves 2.2mm grace (.087”).  Keep in mind that we are looking at the stock clutch.   Adding extra plates not only increases the friction area, it also decreases the installed height of the springs.  That decrease in height increases spring preload.  What’s not to like?  More friction area + more spring force = higher torque limit.  The clutch slip is a thing of the past.   Seems like a good idea, right? Ooooops!   What about travel?  Increasing the stack height of the plates eats up all the travel.  You might end up with an inoperable clutch and/or a broken release cam and/or broken something else.  You just can’t throw in a pair of extra plates. If you start adding plates, that grace evaporates in short order.  The fiber plates are .115” thick and the steels are .062”.  Add one of each (a pair) and your .087” grace just turned into about .090” interference.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:27:05 Here’s what happens if you throw in an extra pair of plates (one friction & one steel) on a stock hub.  The bottom plate gap is now only .092” and the tangs on the plate are starting to dig into the radii in the bottom of the basket slots.  Note that the position of the hub flange has not changed.   There are a few things that I can’t show in a photograph.  The clutch is locked up.  The pressure disk will not move when I push on the spring bolts.  The basket has no play.  When things are correct, you can jiggle the basket around, but with the extra two plates the whole shiteree is rock solid.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:29:22 How about thinning down the plates?  There are thirteen plates.  If you remove .010” from each plate you would reduce the stack height by .130”.  That might fit, but it would be a lot of precise work.  Do you happen to have a surface grinder with a magnetic table?  That would work on the steel plates, but the fibers are a different story.   If the stock clutch has .157” travel, and you add a pair of plates (.115” + .062” = .177”) you reduce the travel to minus .020”.  It’s an interference fit.  Break out the sanders and grinders and lappers and whatnot, and lob .130” off the stack, and you could possibly restore travel to .110”.  That would give you a .040” margin over the release mechanism travel.  It would also reduce the spring installed height by around .047”, which would increase the spring preload.  I don’t think the additional spring preload would be a showstopper, but ya gotta keep that release cam in mind. What about the oil slots in the friction material?  The friction material is right at .015” thick.  You could take .005” off each side.  That would make the oil slots shallower.  I think those are there to provide a path for the oil to be squeezed out when the clutch is engaged.  Would shallower slots cause problems with friction? You can see from this photo that the material is very thin.  The total thickness is .115”.  The metal portion is .085”.  That leaves .030” total friction material, or .015” on each side.  Are you willing to sacrifice 33% of your available friction material?

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:30:37 You should also be concerned about embedding abrasive particles into the soft friction material.  It would probably be best to use some sort of cutter rather than abrasive paper.  The metal core is non-magnetic, so a magnetic vice is not an option.  It’s complicated.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:32:32 How about just adding an additional steel plate?  That would increase the spring preload by 1.5mm (.06”).  It would decrease pressure disk travel by the same amount.  You would end up with total travel around .100”.  It looks like a reasonable option to patch up a worn clutch or even beef up a clutch that’s just barely at it’s limit.  But again, the release cam will be subjected to more stress.  It can probably handle the additional 24 to 28 lbs of total spring load, but there are no guarantees.  For that matter, there are no guarantees on the stock setup either.  We really don’t know for sure why the release cam fails. I think the extra steel plate option might be a good approach for a worn-out clutch.  For instance, if the hub flange is worn down a millimeter or so, adding an additional steel plate would bring the stack height back close to the original height.  You could get a few more miles out of the old horse.  If you add an extra steel plate, it must go on the pressure disk side of the stack.  It won’t fit against the hub flange.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:34:05 You can see here that it would be pretty ugly if you tried to install the steel plate against the hub flange.  The spring load would go through the roof and pressure disk travel would be close to nothing.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:35:37 If you want to install an extra steel plate to compensate for wear or increase spring preload, install the extra plate on the pressure disk side of the stack, like this.  But remember, it will probably increase spring preload and stress on the release cam.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:37:29 With all this talk about extra plates, we haven’t considered spline engagement between the sleeve hub and the pressure disk.  The sleeve hub drives the pressure disc.  They rotate together.  There are male splines on the hub and female splines in the pressure disk.  If you disengage the splines, the spring posts will take the load.  I don’t think they are strong enough.  Also, the splines can misalign and prevent the pressure disk from clamping the plates together. Here’s how much of the sleeve hub protrudes from the plates on a stock clutch with an extra pair of plates.  It only sticks out a little over 1mm (.043”).  The release mechanism travel is .070”.  It would disengage the splines.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:38:47 If the pressure disk disengages from the hub, the splines can hang up.  So, if you choose to mess around with adding plates, keep this engagement in mind.  Make sure the hub protrudes out of the plates at least 2.5mm (.100”) to maintain spline engagement when the clutch lever is pulled.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:40:32 Another consideration is the release mechanism.  The pushrod setup must be correct.  You can end up trying to “bend” the pushrod rather than “push” the pushrod.  When things are correct, the release lever on the clutch cover will be centered between the two marks on your engine case (with all the free play taken up). This one is a little high, it needs a longer pushrod.  Just let the weight of the wrench take up all the free play.  If the end of the lever is too high, install a longer pushrod.  If it’s too low, install a shorter pushrod.  As the clutch wears, the lever position will drop, and you must install a longer shorter (3/24/21) pushrod to compensate.  If you let this setup get too far out-of-whack, the release cam will side-load the pushrod instead of pushing straight in on the pushrod.  That little pushrod is tough.  It’s not gonna give.  The release cam???  I’m not so sure.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:41:57 Anything you do that changes the clutch plate stack height will alter the release mechanism setup.  Replace a worn clutch, you must check the release mechanism setup.  Add more plates, you will most likely have to install a longer pushrod.  It comes in three lengths, 44.5mm, 45.5mm, and 46.5mm.  I suspect you could fabricate one from a ¼” drill blank but the end radii would require good attention to detail.  So far, the three available sizes have served my needs.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:43:16 While dissecting the clutch, I noticed a significant amount of lost motion in the release mechanism.  I could move the lever arm back & forth without the release cam moving.  I took it apart and noticed a lot of wear on the corners of the flats that engage the release cam.  I think that wear might set up a wedging effect that could increase the hoop stress in the release cam.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:44:43 I was able to tighten things up by installing a .008” shim between the shaft and the cam.  The shim takes up a lot of the excess clearance and forces the cam to bear all the way across the flat.  I don’t know if it will prevent the cam from failing, but I don’t think it will hurt.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:46:37 The shim fits between the shaft and the cam.  It is captured on both ends.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:48:01 The ball socket in the release cam was galled.  I replaced the cam.  New cam on top, galled cam on bottom.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:50:04 Up to this point, I had not found any options that looked suitable for my situation.  I needed a way to beef up the clutch without significantly increasing spring force.  That limit on spring force dictated more friction area (i.e. more plates). I knew that the early model (1990-1995) DR650 had a few clutch parts that were interchangeable with our LS650.  Some of the fiber plates had the same part number, as did some of the steels.  That implied that the splines on the hub and pressure disc were the same as the LS.  The hub lock washers had the same part number, so the splines in the hub for the input shaft should be the same.  The early DR650 clutch has thirteen plates (seven fiber plates and six steel plates).  Maybe there’s some options buried in the old DR.  I ordered a well-used DR clutch assembly on eBay to see what I could learn. The DR hub and pressure disk are the solution to the problem.  This shows the DR hub (21410-12D01) next to the LS hub.  You can see that the splines look the same.  The DR hub fits the LS transmission input shaft, and the steel plates fit also.  Note that the boss in the center of the DR hub is a lot bigger than the LS.  The DR pressure disk must be used, or the LS pressure disk must be bored out to suit the DR hub.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:51:19 The DR hub is a lot longer than the LS hub.  The DR hub is just the right length for an additional pair of plates.  Makes sense, the DR came with two more plates than the LS (13 vs 11).

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:52:41 Here you can see that the LS pressure disk won’t just drop on to the DR hub.  The hole in the center of the LS pressure disk is too small.  It would be easy to bore out, or just use a DR pressure disk.  Other than the hole in the center, the two pressure disks are identical.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:53:52 Here’s how the pressure disk should fit.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:55:07 It didn’t take long to figure out that the old DR hub was in bad shape.  It had been rode hard and put up wet.  The steel insert in the center of the hub was loose.  I think I could have run it, but mockup seemed to be a better role for the old hub.  I found another one on eBay and ordered it.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:56:53 Using the DR hub and pressure disk, along with seven standard LS fiber plates and six LS steel plates, things started falling into place.  I substituted a standard fiber plate for the one special outer fiber plate with the wave washer.  Pressure disk travel was .085”.  Just a bit more than the release mechanism travel (.070”).  That seemed like enough grace and the available travel will increase as the clutch wears.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 03:58:37 The bottom disk gap was .170”.  No problems there.  The basket was free to jiggle so no binding on the fiber plate tangs.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:00:48 The hub protrudes .126".  Sweeet!  Won't be any problems with spline engagement.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:02:30 The spring installed height dropped to 24.4mm.  That might need some attention.  It wasn’t going to present a problem with coil bind (that occurs at 19mm), but the spring preload will be increased significantly.  Seemed like a good idea to trim back the release plate a bit to increase the installed height closer to 26mm.  I used a 7/8” end mill to increase the depth of the spring sockets in the release plate.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:03:56 The finished release plate looked good.  You can see the difference compared to a stock release plate.  The final spring height was 25.4mm.  Not too bad.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:06:08 With the new 13 plate clutch fully assembled, some clearance checks were in order.  I installed the clutch cover and placed the transmission in 5th gear.  The output pulley turned easy and there was no audible indication of rubbing.   A quick check with some modeling clay showed that there was clearance all around, but the spring bolts were a little closer than I would like.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:07:39 As the clutch wears, those bolts will move closer to the release mechanism.  A quick trim and I had an additional millimeter of clearance.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:09:13 I left the waver washer assembly out.  It counteracts the clutch springs during engagement and release, but I don’t think it changes maximum spring load which is achieved at full release (when the clutch lever on the handlebar is pulled all the way in).  Leaving out the wave washer should provide a bit more clamping force at full engagement.  Replacing the special outer fiber plate with a standard fiber plate should add about 2% more friction surface.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:10:32 The DR hub had this crazy wire that captured the outermost steel plate, wave washer, and special fiber plate.  I suspect the wire helps to keep all the parts (waver washer & outer plates) together during clutch assembly.  I left the wire out.  It wasn’t a problem since I was eliminating the wave washer.  Seemed to work out OK.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 03/12/21 at 04:15:03 This modification adds about 17% more friction surface while keeping spring load reasonably close to stock.  The lever arm position fell right between the marks with a 46.5mm pushrod, so geometry is unchanged. I’ve put about 100 miles on the hybrid clutch.  It holds WOT just fine.  Not even a hint of slippage.  That’s with stock clutch springs.  It’s much easier to find neutral than the Barnett clutch, and it might even be easier to find neutral than the stock clutch.  Lever pull is light, just like the stocker. It does have a couple of minor glitches.   The stock LS clutch has very progressive and predictable clutch engagement.  This hybrid clutch is not as progressive.  It requires a bit more finesse, especially with a three-inch flywheel.  Anyone with just a bit of experience will have zero complaints about clutch engagement, but a brand-new rider will have a harder time.  I suspect this is due to leaving out the wave washer. It clunks a bit when shifting from neutral into 1st gear.  That mostly disappears once the oil is fully warmed up. For those of you who are pushing the limits, this is a practical approach to beefing up your clutch.  In my opinion, it is safer than installing stiffer springs or shimming springs, and a lot easier than trying to thin out your clutch plates. I hope you find this report informative.  As usual, I welcome your questions and comments. Stay safe, stay well. Mike

Title: Re: Beefing up the Clutch Post by ohiomoto on 03/12/21 at 05:39:07 Cool stuff as always.  We need a a sticky post where you can list and link all of these mods and the detailed information that you put in them.

Title: Re: Beefing up the Clutch Post by Dave on 03/12/21 at 07:16:59 DragBikeMike: Great job finding, fitting and finagling the stuff together! Mike's modified clutch is definitely a beneficial improvement when you have a significant increase in HP

Title: Re: Beefing up the Clutch Post by TheSneeze on 12/02/21 at 09:09:08 Based on your numbers, you lowered the spring seats 1mm?  Installed height went from 24.4mm to 25.4mm.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 12/02/21 at 15:56:24 Yes Sneezy, I ended up with an installed height of 25.4.  I would have preferred 26mm, but there just isn't enough meat on the release plate to allow cutting it back that far.   So, I have 0.6mm more spring preload than stock.  It's working fine.  Still zero slippage after a whole bunch of miles.  It's been thoroughly tested.  It handles everything from the box-stock motor all the way up to the full 97mm flat-top piston with all the trimmings.  The only problem I have encountered is an occasional squeal.  That only happens when I try to start off with heavy throttle and cold oil, or when I screw up and try to start off from a dead stop in 3rd or 4th gear (it's an old age thing). The buggah takes a lickin and keeps on tickin. It should be noted that I don't dump the clutch, burn rubber, or power shift, but it definitely sees more than it's fair share of WOT.

Title: Re: Beefing up the Clutch Post by TheSneeze on 12/02/21 at 16:03:41 I plan on having a local machine shop cut the spring seats for me, since my wife doesn't like the price tag on a Bridgeport knee mill let alone a bench lathe for the round bits.  I keep my eyes on all the estate sales in my area just in case I run across a steal.  Same shop will cut the side cover for the longer starter gear shaft.  Support your local businesses!   8-)

Title: Re: Beefing up the Clutch Post by Dave on 01/09/22 at 16:24:58 I had some time today to work on this clutch improvement. To make the hole in in the clutch basket larger.....I used my lathe and a 1-3/4" (44mm) holes saw.

Title: Re: Beefing up the Clutch Post by Dave on 01/09/22 at 16:25:40 The hole saw did a wonderful job....it cut through the aluminum easily and made a nice tidy hole.

Title: Re: Beefing up the Clutch Post by Dave on 01/09/22 at 16:26:15 The hole was exactly the size it needed to be!

Title: Re: Beefing up the Clutch Post by Dave on 01/09/22 at 16:28:00 I then used a Forstner bit in my milling machine to cut the spring pockets a bit deeper. I had made a fixture to hold the piece and allow me to rotate it to cut all 4 pockets.

Title: Re: Beefing up the Clutch Post by Dave on 01/09/22 at 16:28:37 The Forstner bit cut the aluminum like it was butter!

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/09/22 at 16:32:01 Finding the perfect size HOLE SAW is mind boggling!  Those seem to wobble more than desired making the hole too large (or larger than the listed size).  I guess when you have a lathe and can true it up properly.  Man, I wish I had a lathe!

Title: Re: Beefing up the Clutch Post by Dave on 01/09/22 at 16:32:50 My lathe and milling machine made this work really easy - but I do believe you could do both of these on a drill press if you have a hole saw and the correct size Forstner bit. DragBikeMike did an amazing job of figuring this out.  The amazing thing is how well this all goes together.  Before I took my clutch apart I measured the distance the push rod stuck out, and it was 12.4mm.  I then installed the DR650 inner clutch basket, replaced the outer disc with a new one that is the same ID as all the others, then added another steel and fiber disc....and when I got it put together and checked my push rod length - it was 12.4mm!

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/09/22 at 16:34:02 Yeah, I want a knee mill too....

Title: Re: Beefing up the Clutch Post by DragBikeMike on 01/10/22 at 20:57:17 Nice job Dave.  Love the way you found a simple solution for the tooling.  Looks to me like your Forstner bit has carbide blades.  You're gettin ready to put some serious torque to that rear wheel.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/10/22 at 21:34:47 Seems to me a Forstner bit is a lot like a piloted spot facing end mill.  A search on forstner bits came up mostly with wood cutting tools.  I realize aluminum is softer than steel, but I have used mostly steel working tools.  This is when I needed a spot face for a press in stud head to clear the brake shoes in a drum brake.  Similar designed tool, different name.

Title: Re: Beefing up the Clutch Post by Dave on 01/11/22 at 09:36:03 I was able to get the bike out and ride up/down the driveway to test the clutch.  (A longer ride is not possible as the roads are covered in salt). It works fine - it really doesn't feel any different.  There are 2 new plates that likely need a bit of wearing in - but it engages and releases just fine.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/24/22 at 08:50:02 447F7265747863657E767B64170 wrote: The hole was exactly the size it needed to be! By any chance did you measure what the finished hole size was?  Or what diameter the boss is on the DR clutch hub?  I am still waiting for my DR hub to ship, and it's holding up my machine shop run.  I know you mentioned a 1-3/4" hole saw, but those always cut over size.  If I can find out what size the hole needs to be I can get the parts going at the machine shop now instead of waiting another week of so for that hub to arrive.  Thanks!

Title: Re: Beefing up the Clutch Post by DragBikeMike on 01/24/22 at 18:30:06 The hub boss is 1.730”.  You want clearance similar to the stock setup.  The stock hub boss is 1.335” and the stock pressure disc is 1.340”, so stock clearance is .005”.  I suggest you bore your pressure disc to 1.735” -1.740”. Heads up on this clutch mod, mine started to slip after I threw on a new high flow muffler.  The new muffler flows very close to your black Mac muffler.  So, again I have found the clutch to be a weak link. All clutch components look fine.  All seven fiber plates are .115”.  All six steels are .062”.  The springs all have the same force at installed height as they had when new.  It just can’t handle the power.  Only remaining option is stiffer springs.  I’m gonna go with the early DR650 springs.  I,ve triple checked and they don’t coil bind so that shouldn’t be a problem unless I get stupid and adjust the cable way too tight. It will be a while before I can test it.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/24/22 at 19:31:57 Thanks, DBM

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 01/25/22 at 01:33:19 The sintered throw out is The weak link. If you are going to increase the spring pressure I would suggest keeping a spare throwout around. Getting a hunk of material and making one is the best answer I can come up with. I put a washer under the springs and mine broke.

Title: Re: Beefing up the Clutch Post by Dave on 01/25/22 at 05:57:06 The hole saw left a hole that was 1.770" diameter. The lathe and mandrel was really secure and there was no wobble in the hole saw.  I let the cutter bottom out on the mandrel and get tight....rather than use the pin locking mechanism that allows the cutter to wobble a bit.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/25/22 at 07:37:23 I am already into to the engine mods, so no turning back.  At this point, the 13 plate clutch is better than the stock with these engine mods.  In my mind it would slip less than an 11 plate set up - as DBM said, more surface area.  I will put some thought into the actuation geometry and parts design to see if I can help come up with another solution to the slip issue.  I also have some mechanical engineer friends from my career days, maybe replacing some parts made with stronger materials/design could ease the failure mode of the weak link...

Title: Re: Beefing up the Clutch Post by DragBikeMike on 01/25/22 at 13:36:51 Justin, your concern over the release cam is valid.  I'm kinda outa options.  I don't want to reduce power, so need to focus on the clutch.  It held fine until I threw on my latest muffler design.  That put it over the limit. More info please.   These washers you installed, have any pics?   If no pics, what can you tell us about the washers? Where did you install them, under the springs between the hub and springs, or on top of the springs, between the release bearing and springs? How thick were the washers? Did the washers rectify your slipping issue? Do you still have the washers installed? Do you still have the washers? I appreciate anything you can share regarding those washers.  The info will help me make decisions about my clutch. Thanks, Mike

Title: Re: Beefing up the Clutch Post by Dave on 01/25/22 at 14:35:51 Mike: I wonder if the broken clutch release pawl is caused by the loose fit on the shaft....as much as using washers to increase preload or using stiffer springs? When I had my Cafe' bike apart I took the shaft apart and I saw the same wear pattern as you had....my bike has 15,000 miles on it.  I put in the little metal shim that you invented to tighten things up.

Title: Re: Beefing up the Clutch Post by verslagen1 on 01/25/22 at 15:57:47 why not solder the cam into place?

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/25/22 at 18:18:09 The wear marks in the pictures posted would indicate more force being applied outward instead of only on the flat turning the shaft.  Slop could be a contributing factor in the pawl failure.  Welding or soldering the pawl to the shaft would be a good experiment to see if the pawl would still fail under stiffer springs.  Any more pictures of failed pawls?

Title: Re: Beefing up the Clutch Post by verslagen1 on 01/25/22 at 20:00:35 I suggested soldering because it will fill up the space and not compromise the materials.

Title: Re: Beefing up the Clutch Post by Dave on 01/26/22 at 03:58:09 I have wondered if welding/brazing/soldering steel reinforcement plates on the side of the cam would help to strengthen it.  I don't know how heat would affect the strength of the metal it is made from....soldering would impose the least amount of heat. Here is a thread with photos of a broken cam. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1533781090

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/26/22 at 08:43:03 I am getting in contact with a friend from my working days who is a mechanical engineer and designer.  We will be discussing the possibilities of different materials, soldering, welding, etc.  I will keep everyone posted as the conversations progress.  Depending on the costs, I would not be opposed to solving this issue by making a stronger parts.  Interested in seeing where this goes!   8-)

Title: Re: Beefing up the Clutch Post by Dave on 01/26/22 at 09:53:22 It appears the break happens at the "thinnest" portion of the part that is opposing the load. I looked on YouTube to see if/how welding can be done on a sintered part - I didn't see anything. Here is how sintered parts are made: https://www.youtube.com/watch?v=z5327SSM6G0 [media]http://www.youtube.com/watch?v=z5327SSM6G0[/media]

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/26/22 at 10:17:20 I already know that welding on cast iron has many problems associated with it - cracking in the parent material being the biggest one.  I am really leaning toward the viability of making replacement parts from a stronger material.  The biggest hurdle on this approach will be the cost.  Not just the raw material, but the milling process as well.  With the double D hole shape the tight corners become a concern while milling. I am thinking that soldering the existing parts will not increase the strength enough to prevent the part failure.  Yes, it will close the gaps in the part fitment, but it will also create assembly issues when trying to put it all back together.  This also applies to a weld approach.  Once the shaft and pawl are one piece, you may not be able to get them back in.  Again, this leads me to think that improving the strength of the material used will be the most viable solution.  What the associated costs will be is yet to be determined.  How much money is it worth to solve this issue?  How much would you spend to prevent this failure mode?  Hey, wait!  I thought I retired from this type of work!   ;D

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/26/22 at 11:20:06 So far the general consensus is a 4130-4140-4340 alloy or a tool steel.  The part is hard, so the replacement material needs to be heat treatable.  There is room between the part and the side cover to add some material thickness to the cross section where the failures are occurring.  I am going to take the part over to my local machine shop, which has heat treat capability, and have some discussions on manufacturability and cost estimates.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 01/26/22 at 11:35:48 More info please.   These washers you installed, have any pics?   If no pics, what can you tell us about the washers? Lowe's flat washers, I took dial calipers and shopped for washers within thousandths of each other, I don't remember if more than one went under a spring. It didn't take long before the sintered part splintered. They were the most common flat washers on the shelf. Not extra thin or thick and the other dimensions are nothing odd. I didn't have a slippage problem, not bad,,without the washer s. With them, certainly not. Full disclosure, that was around twelve years ago, because it was my first S.I.L. who destroyed things who was riding it when it broke. It ruined thelongplastic coated chain tensioner that mounts to the actual cam chain tensioner. Sorry if that is confusing. The washers might solve your problem, but you and everyone else who has been in there knows that sintered metal part is the weak link. Unlike a clutch cable issue, the busted throwout isn't something you want to ride with without first Looking behind the clutch cover and knowing a buncha stuff UpInYonna isn't busted and gonna create problems . Some brave and industrious individual otta carefully study it and see how hard it would be to whittle some out of what? Mild steel? Been years since I was in there. I don't remember how they are built, but I Do remember it looked like a real hassle to machine That shape. Would casting be a better answer?

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/26/22 at 13:40:12 An idea worth pondering - using a laser to cut the profile from 4130 sheet, stack them up and weld them together.  Finish it off by milling in the radius for the push rod.  Once at that point it could be heat treated.  This might be worth exploring. EDIT - the part thickness is .391".  Using .100" thick sheet, four pieces could be stacked together to duplicate the part.  4130 has good ductile characteristics.  Material could be added at the cross section where the failures occur (within room of the case).  Thoughts?

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/26/22 at 15:25:34 As with all mechanical failures, once you strengthen the weak link, the stresses are applied to the next weakest link.  My negativity is showing...  we could end up gaining enough strength to break the case.  Being cast aluminum I am a bit worried about the pivot point of the shaft.

Title: Re: Beefing up the Clutch Post by Dave on 01/26/22 at 17:57:53 554A6F68626B67746D060 wrote: As with all mechanical failures, once you strengthen the weak link, the stresses are applied to the next weakest link.  My negativity is showing...  we could end up gaining enough strength to break the case.  Being cast aluminum I am a bit worried about the pivot point of the shaft. I really think the sintered throwout is a really weak "weak link".  The cross section where it breaks is really pretty tiny in comparison to the material in the shaft or the case.  The clutch clamping pressure in the Savage is really pretty light for the size of the engine and amount of torque. I don't think that strengthening the throwout would cause problems elsewhere - provided that the increase in spring pressure is reasonable and not excessive. There is a company near me that has one of those high pressure water jet/aggregate metal cutters.  I know it cuts round holes really nicely - I don't know how accurately it can cut the holes with the flats (maybe they would have to be rough cut and then broached......then the recessed and scalloped hole would have to be machined).

Title: Re: Beefing up the Clutch Post by DragBikeMike on 01/26/22 at 21:22:11 Justin, the intent of my inquiry was to try and determine if there was any chance your washers put the springs into coil bind.  That's why I'm curious about thickness and location. After observing how the springs behave on the spring tester, I am of the opinion that the fractures were related to limited travel rather than spring force.  It's also possible that it was geometry.  As mentioned earlier in this post, get the pushrod too long or too short and you get into "bending" mode rather than "pushing" mode.  I don't see a need for solder, the shim tightens the thing right up and it stays tight.  It's also simple to make and install. I guess I'm gonna find out about the springs.  I'm either gonna use the Barnetts or the DR650s.  The Barnetts don't impress me much.  They lost about 10% of their force after only a few months of service.  The stockers don't lose anything, but their spring rate is too low. If you watch one of these springs on the tester you get a good idea of why I'm concerned about coil bind.  As you compress the spring, the load goes up in gradual increments, nice and smooth.  It plots out in a straight line, right until coil bind.  Then, the slightest bit more compression and the load goes straight up, like from 70 lbs to 100 lbs in only .005" to .010" movement (maybe less).  That sucker's solid.

Title: Re: Beefing up the Clutch Post by Dave on 01/27/22 at 02:44:44 43454A36343337070 wrote: After observing how the springs behave on the spring tester, I am of the opinion that the fractures were related to limited travel rather than spring force.   We have had a few members who have not modified their clutches and have had the clutch cam fail (it appears a new failure may have been posted yesterday).  Some of the cams fail from normal use on normal clutches. The failure that Toksic had was on a stock clutch with stock springs. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1533781090

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/27/22 at 10:47:26 I finally met with my machine shop to go over this part failure.  Very encouraging meeting.  Not only is he the owner of this manufacturing facility, but he is also a metallurgist.  He is recommending using a solid piece of material, laser cut to shape, blanchard ground to thickness, and mill the push rod cup into it.  He is recommending using AR500 steel for this application.  He can hold a .001" tolerance between the flats in the double D hole that the shaft fits into. So here is the deal.  At today's price check through Partzilla, this piece is being sold for just under $10.  I can get a batch of 25 pieces made, but the selling cost would end up around $20 each plus shipping.  How many of you guys would be interested in buying a part that won't fail for twice the cost of the original?  Testing could be done to prove the part strength, but it would come at the expense of a shaft and an original part.  A set up could be made using a torque wrench to find out how many ft lbs it would take to cause the original part to fail.  Then duplicate the test on the new material part.  This would solve both the stock clutch failure mode, and allow those who want to beef up their clutch to do it without breaking parts.  Trying to make just one for myself is not at all cost effective, it would cost me a lot more to do just one.  Let's see if there is enough interest to get this idea off the ground!   8-)

Title: Re: Beefing up the Clutch Post by Dave on 01/27/22 at 12:47:16 Spending $20 doesn't scare me (unless it is for a burger, fries and Coke). I would likely buy 3.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/27/22 at 13:05:04 I already have a spare shaft and actuator pawl, so I can list the breaking torque of the original part, and what torque it takes to break a new one.  I just need enough people to be willing to buy them to get the first run made.

Title: Re: Beefing up the Clutch Post by Dan P on 01/27/22 at 15:53:33 Count me in Sneeze. Cheap insurance for $ 20 !

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 01/27/22 at 17:22:28 Justin, the intent of my inquiry was to try and determine if there was any chance your washers put the springs into coil bind.   I'm sure they were not. I'm just not the guy who would do that. Good point to consider, just, no, not me. There is a ninety degree, inside corner, that is loaded during a shift change. Doing tests to prove a steel billet made, turned part is stronger than the sintered part seems silly. People who want one can get one or don't. It's not worth the cost of proving it.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/27/22 at 22:02:00 Justin, what is your solution to the part breaking?  The approach is "just silly"?  Not sure where your comments are coming from.  Sintered metal is proven to be inconsistent in strength.  Making the part from a stronger material is definitely worth proving the concept.  Have you had a metallurgist back your claims?  Open to discussion on this as long as it's kept friendly.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/27/22 at 22:07:11 For the record - I am not trying to go into business on this, nor am I trying to make a large profit.  I am trying to improve a part that is known to fail, that will be a detriment to my own project bike.  If I can help others who like this bike?  All the better.  I am retired, and intend to do so.  Not worth it?

Title: Re: Beefing up the Clutch Post by verslagen1 on 01/27/22 at 22:21:59 584762656F666A79600B0 wrote: Justin, what is your solution to the part breaking?  The approach is "just silly"?  Not sure where your comments are coming from.  Sintered metal is proven to be inconsistent in strength.  Making the part from a stronger material is definitely worth proving the concept.  Have you had a metallurgist back your claims?  Open to discussion on this as long as it's kept friendly. It's a known fact that billet parts are stronger than sintered parts. And these will be well fitted parts to boot. So maybe what JOG is trying to say, why test it? I would say if you do test, stop at 150 to 200% stronger. Monitor the amount of twist in the shaft too. Where I used to work, we waterjet a lot of parts and it would leave a rough surface prone to cracking. Laser cut was a big no no, and you had to remove the haz of the cut.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/27/22 at 22:27:45 This type of laser cutting is fiber.  Look into it before panning it.  The cut width is .002 - .003".  At my shop we were cutting with CO2.  Much bigger cut width, much more heat.  The fiber laser has no HAZ.  The part can be picked up right after cutting and it is luke warm to the touch.  If the tolerances can be held, and the part is proven to be stronger, why it is it "just not worth the cost of proving it"?  We are just trying to solve a design problem.

Title: Re: Beefing up the Clutch Post by verslagen1 on 01/27/22 at 22:48:32 736C494E444D41524B200 wrote:  If the tolerances can be held, and the part is proven to be stronger, why it is it "just not worth the cost of proving it"?  We are just trying to solve a design problem. It's not a design problem, it's a mfg problem... dam bean counters.

Title: Re: Beefing up the Clutch Post by Dave on 01/28/22 at 04:24:00 425D787F757C70637A110 wrote: For the record - I am not trying to go into business on this, nor am I trying to make a large profit. Several of us have done this a time or two.....none of us are getting rich, and it is more a labor of love.  Lancer provides performance parts, Verslagen makes tensioner upgrades, Arman and I have done some machining.....we likely make $10 an hour for our time. Thanks for taking on the clutch cam issue. And I agree......testing the original part to failure - followed by testing the new part to prove it is significantly stronger is fine.  I don't believe it is necessary to test a new part to failure if the applied force is significantly improved.  It is likely that a 50% improvement in strength is probably adequate.  If we install stronger springs they won't be a lot stronger - as your prediction of breaking other parts will likely prove true.  I think the next weak link is probably that outer piece that holds the center bearing and pushes on the 4 springs....as we just machined part of it away to reduce the spring preload (although we might not have to machine that away if the cam is stronger).

Title: Re: Beefing up the Clutch Post by DragBikeMike on 01/29/22 at 14:02:12 Wow!  AR500 steel, yield 215 ksi, tensile 240 ksi, RC 50 - 54.  That sounds like some good stuff. Sneezy, count me in for 3 copies of that item.  Possibly willing to go for 5 if you don't meet the threshold. I agree, no need to test to failure.  Taking it to 150% of the original item failure point seems adequate to me.  For info purposes, the force required to take the DR springs to 23mm (max anticipated travel) is 356 lbs.  I suspect the DR springs are probably the stiffest any of us would try to use.  The stock springs exert about 316 lbs at 23mm.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/29/22 at 14:25:24 We still need a few more takers to hit the threshold for a manufacturing run.   Four or five more and I will get moving on this.

Title: Re: Beefing up the Clutch Post by badwolf on 01/30/22 at 08:28:56 Sneeze, I'm in for 2.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/31/22 at 07:32:48 I am headed off to the machine shop today to pull the trigger on a run of these AR500 clutch actuator pawls.  I will make sure they know the critical features are the distance from the cup to the shaft centerline, the depth of the cup, and the flat to flat distance on the double D hole.  I am looking forward to seeing how these turn out.  Of course, I will post detailed pictures of them when I receive them prior to shipping.  Thanks go out to all the guys willing to join me in this experiment!  Here's to finding the next weakest link!  Cheers!

Title: Re: Beefing up the Clutch Post by DragBikeMike on 01/31/22 at 10:38:15 Sneeze, I didn't think you would get this started so fast.  Nice job.  Hope this comment isn't too late.  Please make sure the machinist maintains these two critical fillets.  There must not be a sharp corner in the areas circled in red. Thanks,  Mike

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/31/22 at 11:25:54 The part will retain the same profile as the OEM part.  We are tightening up the tolerance and clearance of both the flat-to-flat dimension and the diameter of the double D.  There was as much as .012" of clearance on some of these features.  Crazy.  No wonder there are wear marks on the edges of the flats on the shaft. One change is necessary.  We are cutting these from .25" thick AR500, and they will be fuse welded together using TIG.  The parts will still be ground to the OEM thickness. He does not have any .500" thick AR500, and would need to buy an entire sheet to get it.  This will not detract from the strength of the part as there are no forces being applied to try and separate the halves.  Fuse welding will eliminate any "proud" filet that could reduce clearance to the case.  If this approach makes anyone leery, speak up now.  I will post pictures of the finished parts prior to shipping so everyone can see what they are getting.  The strength increase should be huge with this material, so I looked at the two piece approach as a moot point.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/31/22 at 11:33:28 02040B77757276460 wrote: Sneeze, I didn't think you would get this started so fast.  Nice job.  Hope this comment isn't too late.  Please make sure the machinist maintains these two critical fillets.  There must not be a sharp corner in the areas circled in red. Thanks,  Mike That would introduce some stress risers that would cause a quick failure!  The parts will maintain the stock profile.  I told him there are four critical features: 1) Two double D features - diameter and flat-to-flat 2) depth of the cup feature 3) distance of the cup feature to the double D centerline 4) Those two radii you pointed out. I am looking forward to seeing these and how they turn out!

Title: Re: Beefing up the Clutch Post by DragBikeMike on 01/31/22 at 12:10:01 Won’t welding two 1/4” pieces together place the centerline of the cup right on the parting line? The AR500 is quenched & tempered.  What happens to the mechanical properties once you weld it? The welding doesn’t sound good.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/31/22 at 12:41:06 I will have these concerns addressed prior to cutting any metal.  Stay tuned.

Title: Re: Beefing up the Clutch Post by TheSneeze on 01/31/22 at 12:53:15 Just got off the phone with him.  After voicing those concerns, he actually found a smaller chunk of .500" thick from a different supplier and won't need to procure a whole sheet.  So we are back to one piece, no welding.  I think he was leaning toward the two piece method as they cut .25" thick every day, and didn't have any .500" in stock.  Sorry about the hiccup.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 02/01/22 at 16:29:57 known fact that billet parts are stronger than sintered parts. And these will be well fitted parts to boot. So maybe what JOG is trying to say, why test it? Yep,seems silly. I'd eyeball the new part and if it needs smoothed or something, whoop the Dremel out and slick it up. I could see myself wanting one of those. I didn't see a price.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 02/01/22 at 16:36:02 What we don't know about that Could lead to a problem is We don't know the comparative hardness of the sintered versus billet parts. Might need to heat treat the new part. Engineer time.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/01/22 at 18:07:05 I can try to get the machine shop to provide Material Test Reports on the material used, if they are available.  Usually the reports need to be asked for in advance.  Here is a screen grab from Mcmaster-Carr where you can get it. Material      AR500 Carbon Steel Shape      Sheet and Bar Shape Type      Sheets Thickness      1/2" Thickness Tolerance      -0.01" to 0.03" Tolerance Rating      Standard Width      6" Width Tolerance      -1/8" to 1/8" Length      6" Length Tolerance      -1/8" to 1/8" Yield Strength      200,000 psi Fabrication      Hot Rolled Heat Treatment      Hardened Hardness      Rockwell C48 Hardness Rating      Very Hard Appearance      Plain Temperature Range      Not Rated Flatness Tolerance      Not Rated Coefficient of Thermal Expansion      7.3 × 10^-6 Elongation      12% Material Composition, Boron      0.003% Material Composition, Carbon      0.31% Material Composition, Chromium      0.75% Material Composition      0.95% Material Composition      0.75% Material Composition, Nickel      1% Material Composition, Phosphorus      0.025% Material Composition, Silicon      0.65% Material Composition, Sulfur      0.005% Material Composition, Iron      Remainder Warning Message      Physical and mechanical properties are not guaranteed. They are intended only as a basis for comparison and not for design purposes. Certificate      Material Certificate with Traceable Lot Number Additional Specifications      SDS RoHS      RoHS 3 (2015/863/EU) Compliant REACH      REACH (EC 1907/2006) (07/08/2021, 219 SVHC) Compliant DFARS      Specialty Metals COTS-Exempt Country of Origin      Varies Schedule B      721119.7050 ECCN      EAR99 Exceptional hardness makes AR500 carbon steel more resistant to wear and impact than other carbon steel. And with a yield strength of 200,000 psi, it’s also stronger. That's why it's often used to protect blades and buckets on heavy equipment, or to line truck beds and chutes. While it’s too hard to bend or form, you can cut it with plasma, oxyacetylene, lasers, water jets, or abrasive cutoff saws.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/01/22 at 18:14:06 Everything I have heard about sintered metal from the metallurgist at the machine shop I am using, to several mechanical design engineers I have met through my career (who are now friends), the part strength can very widely and is not consistent.  This would lend credence to the fact that some stock ones have failed without increasing the force being applied.  The AR500 material is far and wide much stronger.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 02/01/22 at 18:21:16 Heat Treatment      Hardened Hardness      Rockwell C48 Hardness Rating      Very Hard As long as the handling doesn't change its properties, it looks like a winner.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 14:06:02 Okay, guys and gals...  I picked up the new parts from the machine shop today.  Yes, it went that quick!  As promised, I am posting very detailed pictures of how they turned out.  Laser cut finish is never perfectly smooth - but before any of you start to tout stress risers, I will post strength measurements in comparison to the stock, sintered part (also as promised).  This material is by far and away a much stronger alloy than any sintered metal could yield.  So here are the pictures from all angles, after which I will post my findings, pro and con.  The testing will come a little later when I have a chance to set up the method and document the results. What I am trying to do here is to be as open and up front on these parts as humanly possible.  I am not going to spend any time trying to sell these to anyone, or get into engineering or scientific arguments trying to justify what these are or will do.  If you want to buy one (or more) great.  If not, I will not try to convince you.  My main goal here is to try and solve a common problem with our Savages, and help the community.  No, I am not going into business with these.  So don't try and force me to put on my stainless steel underwear to keep you from chewing my a$$ off about how you think about these parts.  On with the pictures... Stock part on the left, AR500 part on the right.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 14:06:47 Stock part on the left, AR500 part on the right.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 14:08:44 Stacked comparison.  Stock part on the bottom, AR500 part on the top.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 14:09:36 second stacked view.  Stock part on the bottom, AR500 part on the top.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 14:10:11 Inside finish view

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 14:37:08 Here are my initial findings: VISUAL INSPECTION The parts have been through a vibratory deburr process (a lot like rock tumbling).  This has smoothed out the exterior surfaces.  Vibratory deburr process does not get inside holes.  This is why there are more striations in the ID.  With laser cutting, these marks are always present.  The thicker the material, the more pronounced they are.  Hardness of the material has an affect on the surface finish as well.  The cup milled into them was performed after the vibe finish was applied.  I found some of the cup milling had left a fine burr around the top edge of the feature.  I filed down these burrs.  Some of the batch I needed to scrap due to some bad striations that reduced the cross section of the part.  Again, this is not uncommon with laser cutting.  Overall the visual appearance was much better than I was expecting with my personal experience running a fab shop with a laser. DIMENSIONAL INSPECTION Although I was told the part fitment on the shaft would be tightened up more than the stock part, this did not happen.  The double D hole is within .001" to .002" of the stock part.  The play when installed on the shaft is the same as the stock part.  This disappointed me, but is easily correctable with DBM's use of some feeler gage material inserted between the part and the shaft.  The cup feature is right on in regards to the position in relation to the double D hole.  I found the depth to be within a few thousandths, but I was using the depth gage on my calipers which has a flat end, trying to measure a round bottomed feature.  Not the most exact method.  I will try to use a better set up using my drop indicator with a round tip when I get to the strength testing.  As you can see in the comparison picture (stacked), the overall length does not match the stock part - it is shorter.  This has no effect on the part function in any way.  It will still hold the return spring.  Some of the striations on the inside of the double D hole needed to be filed down a little bit.  The parts are hard, but not as hard as a file.  I used a round/flat jeweler's file to do this.  The striation burrs were just big enough to prevent the parts from sliding onto the shaft.  Once removed, the play was discovered, and found to be the same as the stock part. I will post up the strength test results as soon as I have the data.  My plans are not to ship any of them until I am finished with all of my evaluations.  I am very confident that these parts are a lot stronger than the stock ones, based upon the physical properties of the material alone.  The strength tests will prove that.  I ordered 25 parts, the shop made 30.  After visual and dimensional inspections, I scrapped 5.  Three for severe striations that compromised the wall thickness of the part, and two due to the fact they would not fit over the shaft (no matter how much filing was done).  So there you have it. I absolutely will be running one of these on my hot rodded Savage motor.  If anyone else wants to, just hit me up.  If you don't, that's fine too.  The money I have spent on this manufacturing run was worth it to me just to solve the slipping clutch issue that would happen on MY bike.  If this will help out more of you, great. I am open to comments and friendly discussion/questions.  If you feel like being negative, just don't ask for one.  Peace, out.

Title: Re: Beefing up the Clutch Post by Dan P on 02/04/22 at 15:24:14 Looking good !

Title: Re: Beefing up the Clutch Post by Dave on 02/04/22 at 16:29:30 The look really nice.......amazing how accurately the part was copied. Having to install a shim doesn't scare me....maybe I can just solder or JB Weld it onto the shaft to make it permanent.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 16:49:50 In the case of a failure that would make it necessary to replace your shaft by cutting it in two to save your side cover. I just tried to set up a torque test.  I found a 27mm impact socket fit perfectly.  I started at 20 ft lbs, and increased each pull by 5 ft lbs.  At 35 ft lbs, the shaft started to turn in the lever!  So now I have a used clutch lever coming from Fleabay.  I need to find a better way to secure the shaft, not using the lever.  I think I just discovered the next weakest link! EDIT - this first test was using a stock part to try and achieve a base line breakage point.  I have not done a torque test on the AR500 parts yet.

Title: Re: Beefing up the Clutch Post by Armen on 02/04/22 at 16:57:53 Amazing work! Good on you! Are you planning on having a few made and selling them? I’ll place my order now if you are. Thanks

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 17:10:32 Reply #114 Thirty were made, five were scrapped.  Twenty five are available (well, minus one for me!)

Title: Re: Beefing up the Clutch Post by Armen on 02/04/22 at 17:23:50 Cool. How much? Paypal OK?

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 17:34:36 $20 plus shipping.  I am not starting to ship any parts until the strength testing is complete and results are posted.  You know, full transparency...

Title: Re: Beefing up the Clutch Post by Armen on 02/04/22 at 17:43:17 Thanks No rush Just keep us in the loop Thanks for all your hard work

Title: Re: Beefing up the Clutch Post by verslagen1 on 02/04/22 at 19:12:19 I would mount the shaft between 2 vices clamping the shaft as close to the pawl as possible on each side and apply a force with a 1/4" pin to the dimple. This would be as close to the application as possible.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/04/22 at 19:51:01 I am all ears on how you would measure the force being applied that way.  Mechanically I understand where you are coming from, completely.  From a practical set up stand point, how? Do you mean two vice jaws (one vice)? What instrument(s) would you use to measure the applied force?  The failure mode of the part is the corners of the flats on the shaft are applying outward force on the double D hole, trying to push it apart from the inside.  The rotation of the shaft in the double D hole.  This is the force I was trying to duplicate.  Not by rotating the shaft, but by rotating the part.  Since I am not willing to go out and purchase any special fixtures or measuring tools for this, using a torque wrench (which I have) will need to suffice.  I could cut the shaft short enough to still put the socket over the shaft and pawl.  But testing that way would eliminate any allowable twist by the length of the shaft.  Leaving the shaft full length and pinching the flats of the shaft in a vice eliminates my only method of measuring the force applied, unfortunately.

Title: Re: Beefing up the Clutch Post by Dave on 02/05/22 at 04:55:00 My thought on a test rig would be a flat plate with two blocks attached to emulate the clutch cover.....holes would be drilled in the blocks to do the function of shaft pivot.  A bolt would be tapped into the plate to work as the clutch push rod.....the bolt could be screwed in/out so the length could be adjusted to get the cam properly located. The shaft could either be made from rod with the flats cut in and a nut welded to the end so your torque wrench could be used - or the stock shaft with some form of adapter made that would fit your torque wrench and slip over the arm of the clutch rod. I could try to build something today and/or tomorrow and it won't be shipped until Monday......you likely wouldn't get it until the end of next week.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/05/22 at 07:27:40 Very good ideas, Dave.  Since my clutch arm actually started to twist at the weld, I wanted to try and eliminate that weak point to prove the pawl strength.  Cutting the shaft short enough to hold the flats in a vice and still fit the socket over the pawl would certainly test the pawl strength, but would eliminate any inherent twist in the shaft itself.  Since the weld on my clutch lever has already moved, and I won't weld over chrome plating (bad, unhealthy fumes), I am willing to cut the lever off of mine.  I could leave as much of the length intact as to not leave any twist out of the equation.  My clutch lever will no longer be used on a bike.

Title: Re: Beefing up the Clutch Post by verslagen1 on 02/05/22 at 07:45:55 1A0520272D24283B22490 wrote: I am all ears on how you would measure the force being applied that way.  Mechanically I understand where you are coming from, completely.  From a practical set up stand point, how? Do you mean two vice jaws (one vice)? What instrument(s) would you use to measure the applied force?  The failure mode of the part is the corners of the flats on the shaft are applying outward force on the double D hole, trying to push it apart from the inside.  The rotation of the shaft in the double D hole.  This is the force I was trying to duplicate.  Not by rotating the shaft, but by rotating the part.  Since I am not willing to go out and purchase any special fixtures or measuring tools for this, using a torque wrench (which I have) will need to suffice.  I could cut the shaft short enough to still put the socket over the shaft and pawl.  But testing that way would eliminate any allowable twist by the length of the shaft.  Leaving the shaft full length and pinching the flats of the shaft in a vice eliminates my only method of measuring the force applied, unfortunately. I'll try to set something up later today to show what I mean. Your test applies a torque to the pawl, but this only tests the interface load between the shaft and pawl but lacks the shear load applied by the throw out rod itself. Putting the shaft in 2 separate vices for support and clamping hard on the shaft lessons the load on the shaft by putting it into a double shear configuration which is a optimum. Applying a downward load on the pawl at the throw out rod dimple fully replicates the application.  The one thing I've learned in my many years of product development is test as it is used or you'll be surprised when it fails.

Title: Re: Beefing up the Clutch Post by verslagen1 on 02/07/22 at 10:19:06 Here's a quick set up of the test. Sorry didn't have a clutch pawl handy and never mind the support underneath.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/07/22 at 12:16:03 I only have one vice.  The more I think about this, what I am trying to show is the strength difference between the stock pawl and the AR500 pawl.  As long as twisting force is applied to the double D hole in the pawl, and both are subjected to the same force, it will show the difference in material strength.  I am not trying to prove the geometry or strength of the entire mechanism.  Just the pawl.  Even if the test is not the exact force applied by the stock linkage, it will show the difference in material strength.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 02/07/22 at 16:17:22 What are you testing For? What are you expecting to see? Wear ? Failure? Testing is a reasonable idea when change has been made and the results could be really disappointing, maybe costly . By ditching the Sintered metal and going with a hard steel, unless common sense has entered backwards world, I would Expect to see no problems for many cycles of clutch lever. And the Crumble, Fail simply can't happen. Test your metal before and after the work.. A spring loaded center punch, see what it does before and after the work. Unless you can See a problem, I don't understand not installing it. It might be easier to heat treat them than test to see if you need to. I just wouldn't let the hassle, time, cost,of designing a test bed get in the way. The OEM part is a known, rare,but known problem that absolutely downs the bike ,wherever it breaks. I'd hit it with the center punch before and after the cutting and whatever heat you hit it with. I'm confused about the shaft twisting. Might have read that wrong..

Title: Re: Beefing up the Clutch Post by badwolf on 02/07/22 at 16:37:15 I would think ar500 steel will be way stronger than stock. What I would worry about is the pushrod wearing against it. I had to make a pushrod for mine when I installed a extra steel plate and took 2 tries to harden it enough. If the rod or pawl wear your clutch will lose disingaugement movement. (BAD)

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 02/07/22 at 17:35:35 I wonder how a ball bearing stuck on the rod would hold up.. Metal polish and a drill and the rod and throwout are lapped to fit.

Title: Re: Beefing up the Clutch Post by Dave on 02/07/22 at 18:10:55 0A151314090E3F0F3F07151952600 wrote: I wonder how a ball bearing stuck on the rod would hold up.. Back in the 70's when Japanese bikes used to have the clutch push rod go from the left side of the bike and push all the way across the bike though the center of the transmission input shaft - it was common that the shaft had a left and right half and a steel ball in the center. It would be possible to do that on the Savage - but I really don't know how much wear to expect when the clutch push rod has a ball bearing built in already.  Anytime you pull the clutch lever and apply pressure the bearing will likely turn....and the entire mess will be getting a good amount of oil spray when the engine is running.

Title: Re: Beefing up the Clutch Post by badwolf on 02/07/22 at 18:36:43 The first pushrod I made wasn't hardened enough and mushroomed over, shortning it. Dave, your a engineer, is that stock pawl made from that stuff cause it's hard and will standup to the wear from the pushrod? I have never had any experence with that stuff, that I knew of.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 02/07/22 at 19:48:18 I think they chose sintered metal because it does the job and doesn't require machine work. A given amount of powder, in a die,tremendous pressure is applied, boom ,,you have a part. Why they didn't radius in the corners, IDK. Maybe it's not important with sintered metal. But they Do break.

Title: Re: Beefing up the Clutch Post by Dave on 02/08/22 at 02:23:21 0002110F11130B020A11630 wrote: The first pushrod I made wasn't hardened enough and mushroomed over, shortning it. Dave, your a engineer, is that stock pawl made from that stuff cause it's hard and will standup to the wear from the pushrod? I have never had any experence with that stuff, that I knew of. What JOG said - I believe they chose it as it was the cheapest way to make a part that would be adequate for the job.  The part can be made simply - the only apparent machining is the recess for the rod.  (The forming process is just like the Playdo Fun Factory!) I have made clutch push rods before, and I use drill rod (drill blanks that have not yet been machined).  It is hard and you cut it with a grinding cut off wheel, and shape the end by installing it in a drill and spinning it while you grind/sand the radius on the end.  There is no need to try and harden it....the stuff is already hard.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/11/22 at 16:16:01 I went back to the machine shop today so we could perform a hardness test on the OEM and AR500 parts.  The test used was a surface hardness test only.  The hardness on the sintered metal is an unknown - we really don't know anything about the composition of the sintered metal, either.  All we can do is run comparison tests. OEM PART We tested two OEM parts, twice each.  The hardness readings were Rockwell C 39.5  The readings between the four tests, two on each part, was very consistent.  In the picture, one OEM part has three dimples - the third dimple is from the initial test we did when I brought him the part to inquire on a mfg run. AR500 PART We only tested one part, but took multiple readings.  The readings were (again Rockwell C scale) 37, 39, and 40.3  The reading were not as consistent as the OEM sintered part, but very close to the same hardness. Since the AR500 is rated at an average of 48 C, some temper was lost during the laser cut heating the part.  The depth of cut versus the cross section of the part configuration contributed to this.  He estimated the parts could have gotten upwards of 5-600 degrees for a short period of time.  This hardness test is a surface test only, and does not reveal anything about the tensile strength throughout the cross section of either part. I have decided that since I am not willing to spend money on fixtures or gages to measure destructive strength tests that accurately duplicate the force applied in the design application, I will go ahead and ship the parts to whoever is interested in running one.  I know that this material is no where near as brittle as sintered metal.  I am not willing to invest any more money into trying to prove it.  Feel free to do your own research on the physical properties of each of the two materials (we don't know the composition of the OEM material,  but there is a lot of data on the powdered metal process pros and cons).  If the people that were interested initially still want to buy one or more, PM me your addresses and I will start to get postage or shipping costs.  If you decide not to, that's okay too.  It is my conclusion that the OEM part failures are more than likely due to the sintering process yielding inconsistent part strength - possibly due to material flaws during processing.   Peace, out.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 02/11/22 at 16:54:21 Every twenty minute job is a stripped thread away from a three day ordeal. BRILLIANT!! .  I know that this material is no where near as brittle as sintered metal.  I am not willing to invest any more money into trying to prove it. I've been waiting for that.

Title: Re: Beefing up the Clutch Post by Dave on 02/11/22 at 17:07:23 I think more important than how "brittle" the material is - would be the "tensile" strength. I certainly don't know much about powder metal - but it would seem to me that the compressive strength readings of the sintered metal could be similar to steel - while the tensile strength could be far lower.  The heating and congealing of metal powder could create a part that is resistant to compression - but not nearly as good in tension.  (The thin part of the pawl is breaking under tension.....not compression). Send me my 3, and I am likely to set something up and see what "gives"!

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/11/22 at 18:17:13 It is in my opinion that the AR500 part will bend before breaking when pushed to it's limit.  The sintered part will shatter before bending.  This opinion is worth everything you paid for it, so take it at face value.  ;)

Title: Re: Beefing up the Clutch Post by DragBikeMike on 02/12/22 at 11:49:49 Thanks very much for those hardness readings.  The two parts are amazingly close in hardness. For carbon and low alloy steel, RC 39 to 40 should correlate to approximately 177 to 184 ksi tensile.  I agree that the wrought material should be more resistant to fracture. Since the AR500 is billed in the tensile range of about 240 ksi it seems as if it has lost some of its hardness as a result of the laser cut.  That might be a good thing.  Might improve ductility, make it less prone to fracture. Totally cool how you got these things manufactured so fast.  You seem to have a really good connection with the machine shop, and the shop seems to have remarkable capability.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/12/22 at 12:00:30 I am currently waiting for them to cut out the combination clutch/flywheel tool and spacers.  Since they cut .25" AR500 almost every day I told them to nest them in one of their sheets of .25" thick.  The file said to use 3/16" (.188"), but that would require getting a special sheet.  So next week I will post some pictures of the tools needed for engine tear down and reassembly.

Title: Re: Beefing up the Clutch Post by TheSneeze on 02/16/22 at 14:16:17 5153405E40425A535B40320 wrote: Sneeze, I'm in for 2. Let me know if you are still interested.

Title: Re: Beefing up the Clutch Post by badwolf on 02/16/22 at 17:23:53 Yes, let me know your details, you can message me here.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:24:53 4/8/22 Continuation – Testing Sneezy’s Release Cam The clutch now has 13,300 miles on it.  Aside from one false alarm when the transmission failed, it has performed flawlessly.  All of the clutch components checked out perfectly and I reinstalled it in my spare engine.  I’ve been running it in the spare engine for several months now.  That engine is no slouch, so the special clutch is seeing plenty of torque.  It works good. I wanted to install one of Sneezy’s special release cams when I assembled the spare engine, but I wasn’t completely sure that the AR500 cam would hack it, so the spare went back together with a stock release cam. I am waiting for various parts to forge ahead with my new 97mm flat-top engine, so I had some breathing room to mess around with the release cam.  Time to see how strong Sneezy’s hot-rod release cam is. To do a proper test, you need to know how much force the stock system is subjected to.  I had this old beater tool for Harleys.  It was perfect for measuring torque on the Savage release lever.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:25:49 I determined where the release lever is situated when the clutch is fully disengaged.  The bottom of the lever lines up with the top mark on the crankcase.  It took a measly 140 inch-lbs to rotate the lever to the fully disengaged point.  So that should be the starting point for the test.  I would like to see a release cam that can handle at least twice the expected load, so 280 inch-lbs is my minimum acceptable limit.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:26:44 Now I needed a way to twist up the release cams.  A grade-8 bolt fit the bill.  Super strong, super cheap, machinable.  An hour or so later I had this.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:27:34 A chunk of scrap 6061 aluminum and I was ready to rock-n-roll.  The test rig looked like this.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:28:16 A look from a different angle.  I think this will approximate actual conditions.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:28:54 Considering what I was about to do, I figured a scatter shield was in order.  A chunk of wood ought to be safe.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:29:31 And of course, a face shield was a good idea.  Don’t wanna take a ricochet in the eye.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:30:13 First up, a stock cam.  I did a 5X visual and it looked perfect.  There were no visible defects.  A nice coat of moly-lube will ensure that the torque is applied smooth and consistent.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:30:55 To monitor for yielding, I measured from the floor to a reference mark of the handle of the torque wrench.  First apply normal torque (150 inch-lbs) several times, then with just the weight of the wrench measure from the floor to the reference mark.  To make sure the measurements were consistent I marked a location on the floor where the tape measure would be placed.  So, I started with a reference dimension of 54-15/16”.  I figure after a few cycles the shaft will bed into the cam and the reference measurement will decrease.  After the two parts bed in, if the reference measurement continues to decrease it indicates that the cam is yielding, the shaft is yielding, or both.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:31:50 First stop, 200 inch-lbs.  I cycled it a few times to 200 inch-lbs.  The reference dimension dropped to 54-7/8”.  Probably bedding in.  So far so good. Next stop, 250 inch-lbs.  I cycled it a few times to 250 inch-lbs.  The reference dimension remained at 54-7/8”.  That’s good, no yielding. Next stop, 300 inch-lbs.  On the second cycle, “POP”.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:32:29 Not too impressive.  No wonder these things fail.  It was a clean break.  There’s no evidence that the cam was failing over a long period of time.  The entire fracture was dull grey indicating that it was an instantaneous failure.  If it had been failing due to fatigue, the crack would have started and then migrated over time, resulting in polished areas where the surfaces continually rubbed on each other as the crack ran its course to failure.  This one was simply a failure resulting from too much stress.  As expected, the sintered material has almost no ductility.  There were no signs of yielding prior to the failure, which indicates the yield point is very close to tensile strength.   Just look at that break.  No wonder it only costs $10 bucks.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:40:46 Next up, Sneezy’s AR500 release cam.  I had to dress it up a bit with jeweler’s files to get it to slip onto the test shaft.  It was quite a bit looser by the time I was done.  Oh well, hope that didn’t screw things up. After a few cycles at 150 inch-lbs, it was time to put it to the test.  The reference measurement was 53-5/16”.  I attribute the drop to the loose fit and a slightly deeper ball socket for the pushrod. First stop, 200 inch-lbs.  I pulled it five times to 200 inch-lbs.  The reference dimension remained at 53-5/16”. Next stop, 250 inch-lbs.  Same drill, five pulls to 250.  The reference dimension remained at 53-5/16”.  Lookin good. Next stop, 300 inch-lbs.  Five pulls later it had not snapped.  I think that’s a good sign.  The reference dimension dropped 1/16”.  It was now 53-1/4.  Was it yielding or bedding in? Next stop, 350 inch-lbs.  Another five yanks on the T-wrench.  Things were lookin good.  The reference dimension dropped another 1/16” to 53-3/16”.  Hmmmm?  Somethin might be yielding.  Time will tell. Time for some serious twistin.  Have to admit I was getting a bit nervous.  I was pullin on that long handle pretty hard.  But what the heck, the stocker snapped and it didn’t kill me.  No guts no glory.   Onward to 400 inch-lbs.  Let’s get serious, go for ten pulls.  So, ten pulls to 400 inch-lbs and it was still in one piece.  The reference had dropped to 53-1/16”. I was getting froggy.  Didn’t hesitate to amp things up to 450 inch-lbs.  Ten pulls later the reference dimension was still at 53-1/16”.  I’m likin that. The torque wrench only goes to 600 inch-lbs.  I didn’t want to have the thing snap when I had the needle buried, so I decided I would go to 500 inch-lbs and call it a day.  Ten pulls later the release cam was still in one piece.  Wow!  That's 42 foot-lbs.   The reference dropped to 52-7/8”, so we were lookin at a change of 7/16”.  Over a span of 21” (the wrench is 21” long) that’s pretty much nothin (2%).   The post-test visual inspection will tell the story.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:41:29 Sneezy’s release cam passed with flying colors.  Visual inspection showed that it was in perfect condition.  No evidence of any sort of bending.  Inspection at 5X didn’t reveal any cracks but it would be impossible to say that there are no cracks.  The striations from the laser cutting process make it impossible to do a valid 5X inspection.  All’s I can say is that I couldn’t see any cracks when I inspected it with my magnifier. Looks good to me.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:42:06 Here’s a shot of the other side.  It took 42 ft-lbs of torque and didn’t even flinch.  That’s no guarantee that it won’t develop fatigue cracks over time, but I think that is highly unlikely given the expected load.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:43:05 One problem I anticipate is adjusting the release lever position.  The Sneezy-cam has a ball socket that is a bit deeper than stock, and as previously mentioned, the fit might end up a bit looser due to the filing required to slip it onto the shaft.  That’s gonna require a longer pushrod. The pushrods only come in three lengths.  The longest available pushrod may not be long enough.  I have been using shims to fine tune my lever position.  I make the shims from valve spring shims.  You can get them from Competition Cams, Crane, Isky, Summit, Jegs, etc. These (on right) were made from shims that came with a set of RD valve springs.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:43:47 You install the shim between the push piece and the release bearing.  The shims come in .010” and .020” thickness, so you can fine tune the pushrod in quarter-millimeter increments.  With these shims, it’s easy to dial the lever position right down to the gnats-a$$.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/09/22 at 00:44:29 Hats off to the Sneezer.  Killer release cam.  Looks like this might be just what the doctor ordered.  Thanks for your hard work on this one Sneezy.

Title: Re: Beefing up the Clutch Post by Dave on 04/09/22 at 02:57:50 Great test methods as usual......Thanks for doing this. I had a clutch case and some stock and Sneezy cams sitting in the corner of my shop collecting dust waiting for a day when I could get some form of test devised.  My test method would not have been nearly as precise and measurable as the one you devised! It appears the laser cut release cams could handle some big increases in spring pressure - but then the weak point will likely become the outer plate that holds the bearing and pushes on the spring......especially the ones that have been machined to allow more clearance for the extra plate in the DR650 clutch modification you devised. But you have so far proven that bigger/badder/stronger springs may not be needed....and that the release cam that Sneezy had built is far superior to the stock one made from metal pasta.

Title: Re: Beefing up the Clutch Post by Gary_in_NJ on 04/09/22 at 06:48:02 That was some good qualification testing.

Title: Re: Beefing up the Clutch Post by TheSneeze on 04/11/22 at 09:09:35 DBM - thanks for setting up this test.  Unfortunately I do not have the equipment in my shop to set that up (1-2-3 blocks, overcenter clamps, etc.).  After my initial investment in manufacturing these, I was not willing to start buying more tools and equipment (I know, you can never have too many tools!) at this point.  I really appreciate the time you have taken, and the compliments. Note - I have about nine left if anyone else is still interested...

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 04/11/22 at 09:29:59 I don't know how to use online pay,but I Do have a checkbook.. The picture of the broken one looks very familiar, even After all those years..

Title: Re: Beefing up the Clutch Post by DragBikeMike on 04/14/22 at 11:32:53 All the kudos go to you Sneezy.  You came up with a solution to a long-standing problem, took the initiative to do something about it, and were kind enough to allow all of us to benefit from your effort.  You did the work, we get the goodies. I'm almost at the 3500 mile oil change interval.  When I change oil I will be pulling the clutch cover to inspect the cam chain tensioner.  I will change the release cam at that time.  I will let you all know how that goes.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 04/14/22 at 17:14:19 I'll get the check out this weekend.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 05/12/22 at 14:50:38 I installed the Sneezy cam at the 3500 mile oil change.  It was an easy installation.  Had to use the .008" shim between the shaft and the cam to tighten up the fit.  So it was essentially the same fit as the stock OEM cam.   To achieve correct lever position, I ended up removing the .020" shim between the release bearing and push piece, and installing the longest OEM pushrod (46.5mm).  The lever ended up exactly centered between the two marks on the case. Lever pull and clutch action remain unchanged.  It feels exactly the same as it was with the stock OEM release cam. I inspected the stock OEM cam that I removed.  Under 5X magnification there are no visible defects.  I have no reason to suspect that the Sneezy Cam won't hold up just as well.  I currently have 667 miles on the Sneezy cam and it's smooth as silk. The only issue I noted was the Sneezy cam sits a bit skewed on the shaft.  I don't see that as being much of a problem.  I'll gladly take the skew in exchange for twice the strength.  You can see the slight skew here.

Title: Re: Beefing up the Clutch Post by Noble_Savage on 07/04/22 at 23:29:29 Sneezy Do you still have any cams available? Tried to dm but im still a newbie. Thanks.

Title: Re: Beefing up the Clutch Post by TheSneeze on 07/05/22 at 08:48:42 Yes I do.  Send me an email and we can exchange details

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:33:45 7/6/23 The odometer now reads 50,805 miles.  I have been running the hybrid clutch for a little over 36,000 miles.  For the most part, it has proven to be reliable, but it does have its quirks & limits.   From early on, the beast developed this squeal that was accompanied by grabby engagement.  It would get to the point where I had to remove the clutch cover and tighten up the clutch hub nut.  I never found any of the plates worn, and the hub & pressure disk always looked fine, but about every 1000 to 2000 miles I needed to tighten up the hub nut to eliminate squeal and grabby engagement. Dave was running a hybrid clutch and he was also having trouble with the squeal.  He felt that the absence of the wave-washer was the culprit. The hybrid clutch seemed to handle the power just fine.  I used it all through the Evolution of a HotRod project.  No hint of slippage (even with the 97mm flat-top piston engine).  I was chewing up transmission gears but the clutch was holding…..until……I built a 97mm pop-top engine with a decked cylinder, DR cam, big valve head, Mac header, and a really good muffler.  The hybrid clutch couldn’t hold that power. Just like my other encounters with clutch slippage, all the clutch components were fine.  No worn plates, no weak springs.  The clutch simply couldn’t handle the power. So, why does it squeal & grab, and how can I increase the load limit?  I’m in the power game.  I can live with a little squealy grabby stuff, but no way can I accept slippage.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:34:58 Let’s look at squeal & grab first. One thing I noted early on was every time I tore it apart for the squealy grabby stuff, I would find the thrust washers heavily worn and the basket spacer with bronze deposits.  It was clear that the basket was binding on the spacer.  The basket has a bronze bushing that runs on the spacer.  The spacer is pinched between the thrust washers, and it should turn with the input shaft, but it was evident that the spacer was turning on the input shaft (instead of with the input shaft) and wearing into the washers.  Essentially, the spacer was turning with the basket. Look at the wear on this thrust washer.  Only thing that could cause that is relative motion between the spacer and thrust washer.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:35:45 Here you can see the bronze deposit on the spacer.  Also note the wear marks which indicate that the bronze bushing is running skewed on the spacer (wear at ends, none in center).  Seems like the basket is tipping as torque is applied.  That causes the bronze bushing to bite the spacer.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:36:53 It seemed to me that Dave’s suggestion on the wave-washer had merit.  While I don’t pretend to understand everything there is to know about the wave-washer (it’s a mystery to me), I can see how the wave-washer could facilitate more uniform clutch engagement.  Problem is, the wave-washer separates the outermost plates.  To transmit torque, we want to pinch all the plates.  As such, the wave washer will most likely reduce the load that the clutch can handle.  It also requires a slight reduction in friction surface (about 2%) because the special outer fiber plate has less friction surface than all the other fiber plates.  Less friction surface will reduce load capability. One thing in favor of the special the special outer fiber plate is its thickness.  It is slightly thicker than the other friction plates (.136” vs .115”).  That will increase the stack height, which will reduce the spring installed height and increase spring pre-load. Thank goodness for the Sneezy cam.  With Sneezy’s heavy-duty release cam, additional spring force may not be an insurmountable problem.  I’m gambling that the Sneezy cam can handle the additional preload resulting from the thicker outer plate, and also handle any additional preload required to hold the power I am currently making.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:37:51 Exactly how much force are we dealing with?  With the wave washer installed, the inner plates will pinch long before the outer plate.  How much of the spring force will be used up trying to compress the wave washer to the point where the outermost plate picks up load? I set up a test.  With the wave washer installed, I measured how much force was required to lock up the outermost plate.  The outermost plate is at the bottom of this setup.  As I applied pressure, I could reach a point where I can feel the bottom friction disc start to drag, bite, and then lock-up.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:38:33 At 120 lbs., I could still move the outermost plate (the one at the bottom of the picture), all the others locked up solid at about 10 lbs.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:39:17 It locked up at 125 lbs.  Wow!  That’s almost half the spring preload.  Ya gotta use up almost half of your available spring preload to get any work out of the outermost plate.  That wave-washer is robust.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:42:06 Time to gamble. The Sneezy cam was my ace in the hole.  If I used the wave-washer to resolve the grabby-squealy problem I would lose some pinching force, but the Sneezy cam might allow me to increase spring preload to compensate for the wave-washer, plus add a few more pounds to resolve the slipping issue.  There really was no other option. I installed the wave-washer and special outer friction plate.  I used my Barnett plates along with one regular stock Suzuki plate.  The hope is that the Barnett material has a higher coefficient of friction. To increase preload, I installed one thicker steel plate (ala old DR650 Model R/S part # 21451-05A00) along with Barnett springs.  The thicker outermost fiber plate along with the thicker DR steel plate reduced the spring installed height to 25mm.  Note: I had previously mentioned to some forum members that the installed height was 24mm, but I forgot that I had modified my release plate to relieve some of the preload.  The installed height ended up right about 25mm using the modified release plate along with the chop suey clutch pack.  The combination of the shorter spring height and stiffer springs might be enough to hold the power. I checked the torque required to cycle the release arm.  It was now right at 150 inch-lbs at full release.  That correlates nicely with my spring data.  The Barnett springs exert 76 pounds of force at 23mm.  The installed height is 25mm and the full release height should be about 23mm.  Four springs at 76 lbs works out to 304 lbs force.  The release cam lever is 0.5” long so 150 inch-lbs yields 300 lbs force.  I think that’s pretty close.  Science, it works every time. This graph provides some useful data on the spring characteristics.  If these Barnett springs can’t hold the load, I will be forced to resort to the early model DR springs (part # 09440-20013).  Those puppies coil bind at 22mm so it will be a squeaker.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:43:38 How did it work?  So far so good. It’s holding the power, but I’ve got the engine dumbed down a bit.  Runnin super-fat to guarantee no detonation while I test my main bearings and modified lubrication system.  It still makes a ton of power, but there’s a bit more lurking in there.  As I said, so far so good, no slipping. The squealy-grabby issue seems to be long gone.  I’ve run maybe 3700 miles since setting it up with the wave-washer.  Absolutely zero squealy-grabby.  Engagement is smooth and predictable.  For quite a while I had trouble with clunky shifting and finding neutral, but I found that if I decreased the free-play at the hand lever from 1/8” to 1/16” those issues were resolved.  As long as I keep the free-play at 1/16”, everything works normal. In the interest of full disclosure, I have a highly modified lubrication system.  I am running about 66% higher oil pressure.  That means I’m supplying a lot more pressure to the clutch basket bushing, which should mitigate any binding.  That may have something to do with the elimination of squealy-grabby engagement.  But Dave also installed the wave-washer in his, and his squealy-grabby issue went away too.  I believe Dave’s oil system is stock.  I’m gonna stick my neck out and say that the wave-washer eliminates squealy-grabby.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:44:23 Reducing the free-play to eliminate drag made me concerned about case deflection.   Was I losing release travel to case deflection.  If the case is deflecting, something will fail eventually.  So, I checked the deflection with a dial indicator.  It’s only about .003”.   That works out to a little over 4% of available travel.  Not a big deal in terms of clutch drag, but it could be a big deal in terms of clutch cover durability.  I squeeze that lever hundreds of times every ride.  Fatigue is inevitable.  That linear indication looks questionable.  Inspection at 5X magnification indicates that it’s a scratch, but I’ve been fooled before.  I must keep an eye on that.  Let’s hope it’s just a scratch.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:45:00 Reducing the spring installed height to increase preload moved the release plate to the left.  It was already to the point where I had to use a shim between the push piece and the release bearing in order to achieve correct lever alignment with the marks on the crankcase.  That was with the longest pushrod.  Now I had to resort to a spacer instead of a shim.  I simply don’t have much to work with anymore.  Look at that spacer.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/07/23 at 00:54:21 So, the hybrid clutch requires the wave-washer for smooth, consistent, and progressive operation.  You will need to adjust the clutch lever free play so that it is minimal (for me, that was 1/16”) in order to eliminate clutch drag. The hybrid clutch, with its additional friction surface, can’t hold all the power that you can potentially make.  It works fine up to a point, but past that point you need more spring pressure to hold the power.  Bottom line, if ya wanna play ya gotta pay.  Get a Sneezy release cam, because you ain’t gonna be able to jack up that spring pressure without the Sneezy cam. I’m currently hangin on by a thread.  The clutch is holdin the power, but I’ve got the motor dumbed down.  Two days ago, I dropped my needle one-notch.  That amped up my power.  It’s frisky.  If the clutch continues to hold and I don’t end up with a bunch of metal chips on my drain plug, I will pull back on the main jet.  If the clutch holds, time to start thinkin about another engine combo (assuming the main bearings and trans hack the mission too). I love this stuff. Hey Sneezy, got any more cams?  Can you have more manufactured?  For yooz guys on the fence, if you have any inclination to make a bit more power (even the slightest inclination), you might wanna get one of these release cams and hang on to it.  It will be your ace in the hole.  These guys don’t grow on trees and they are unobtanium at your local Suzuki Dealer or Independent Shop. Hey Dave, I know you recently posted on your release cam failure.  Anything new to share?  How’s your wave-washer workin out?

Title: Re: Beefing up the Clutch Post by Dave on 07/07/23 at 03:48:10 Mike: Yep......I installed the wave washer and thicker outer plate, and the annoying squeally/grabby issue is gone. I replaced the thrust washers as they had noticeable wear on them.  Prior to doing this I had to be slow on engaging the clutch - if I let it out too rapidly the squeal would occur. My oil system is stock, I am using stock clutch springs and Barnett Kevlar fiber discs and now the Sneezy cam (I broke the stock one a month ago). When I installed the thicker outer plate and wave washer I had to make my own push rod, as none of the factory ones were long enough. I cut a section out of a long aircraft drill and shaped the ends curved on a grinding wheel.....then polished them smooth with sandpaper while spinning them in my drill press. It took several attempts to get the length just right.....I kept grinding off a little bit at a time to get the lever in the proper operating range.  (I know you use shims under the throw out bearing.....I didn't have any appropriate shims/washers to do that). The clutch works really smoothly and it doesn't slip.  Like you I am finding neutral at a stop a bit difficult - but I adapted and would just find neutral as I was just about to roll to a stop.  Most times I can find neutral as I go from 2nd gear and push lightly down on the pedal and it now has become routine.

Title: Re: Beefing up the Clutch Post by TheSneeze on 07/07/23 at 08:24:38 DBM - as of this morning, I only have a couple left.  I need to keep one for my hot rod motor under construction, and two sold this morning.  Yes, I can have another batch made, but the rate of sales dropped way off after the first volley.  Minimum production run is 25.  Once I run out of stock, I will see if the demand will support another run.

Title: Re: Beefing up the Clutch Post by goofin on 07/07/23 at 09:01:10 56496C6B616864776E050 wrote: DBM - as of this morning, I only have a couple left.  I need to keep one for my hot rod motor under construction, and two sold this morning.  Yes, I can have another batch made, but the rate of sales dropped way off after the first volley.  Minimum production run is 25.  Once I run out of stock, I will see if the demand will support another run. I sent you a message, I definitely want one.

Title: Re: Beefing up the Clutch Post by DragBikeMike on 07/08/23 at 19:08:56 One thing I forgot to stress.  My stock clutch, like totally stock, handled over 41 horsepower just fine.  Not too many forum members will take their engine that far, so the stock clutch can hack it for the average bear.  For those individuals, the Sneezy cam is still an important piece of hardware because we consistently see failed release cams on relatively stock engines, or engines in a mild state of tune.  The OEM release cam is junk, and when it fails it has the potential to wreck your engine.  Chunks of that sucker get tangled up in your primary drive and it's gonna break something, BIGTIME. For engines that get a decent upgrade in the power department, the stock clutch can be modified to handle the additional power.  As long as you have a Sneezy cam, all you will probably need is a set of the Barnett springs.  If that doesn't hold the power, then a set of the old DR springs should do the trick.  The Sneezy cam combined with a set of springs is a very inexpensive upgrade, and it should get you puttin that new found power to the ground. The hybrid clutch, the one this post was all about (seven fiber plates, six steel plates, DR clutch hub), should only be needed when you start gettin serious with the horsepower.

Title: Re: Beefing up the Clutch Post by TheSneeze on 07/10/23 at 21:42:57 All that have sold, are shipped.  My remaining inventory is 3.  When these are shipped I will start another run.  There will be a couple of weeks lead time on any others.

Title: Re: Beefing up the Clutch Post by justin_o_guy2 on 07/10/23 at 23:48:41 Because it bears repeating The OEM release cam is junk, It's sintered metal and it has an internal absolute perfect 90,with No radius. I had put washers under my springs,, but I wasn't the one riding it, my first ex SIL , who, well,, he probably pulled the lever All the Way to the handlebar,, but others have seen failures on completely stock clutches.

Title: Re: Beefing up the Clutch Post by zevenenergie on 07/11/23 at 09:21:18 I wonder, that thing is sintered because it had to be very hard (I think). Are those replacements also hardened? What steel are they made of?

Title: Re: Beefing up the Clutch Post by TheSneeze on 07/11/23 at 15:00:02 Sintered, or powdered metal, is very brittle.  The clutch cams I had made are AR500 alloy.  The same stuff used in armor plating.  Look it up on the interwebs and you can read about the properties of it.

Title: Re: Beefing up the Clutch Post by Dave on 07/13/23 at 04:59:45 4A4C433F3D3A3E0E0 wrote: One thing I forgot to stress.  My stock clutch, like totally stock, handled over 41 horsepower just fine.  Not too many forum members will take The hybrid clutch, the one this post was all about (seven fiber plates, six steel plates, DR clutch hub), should only be needed when you start gettin serious with the horsepower. As DragBikeMike says - the stock clutch works well for stock and mildly modified engines.  If your stock clutch is slipping with a stock engine there is something wrong with the clutch and it needs some maintenance. My engine has a 95mm Wiseco, Performance Cam, Ported Head, 38MM Mikuni Round Slide, Big Foam Filter and good exhaust.....I don't make DragBikeMikes' 41 HP - but it is noticeably more HP than stock.  I also have very tall gearing and the engine turns 4,000 rpm at 70mph in 5th gear. My stock clutch never slipped when it was fully engaged.  If I was hard on the throttle and shifting through the gears - there was a slight lag in clutch engaging fully if I got on the throttle hard as the clutch lever was being released.  When I has accelerating hard I made sure the clutch lever was fully released before I applied a lot of throttle, and I rode the bike that way for about 14,000 miles without any issues. Recently I did the DR650 clutch modification and it grabs better than the stock clutch.  The DR650 clutch hub that is needed is a bit expensive to buy and a little rare....the ones on eBay are often offered as the entire clutch assembly.  (There is one seller on eBay that bead blasts all the parts he sells to make them look better - don't buy that one as the friction surface that is polished has been ruined by the bead blasting). I did the DR650 modification and used the stock clutch release cam as the Sneeze version was not yet available.....my clutch cam broke after a few thousand miles and did some damage in the process.  It damaged my clutch basket, the DR650 clutch hub, one fiber and one steel plate......it was likely $200 worth of parts that was damaged if you buy the replacement used (more if you buy them new). Everyone who has the mechanical ability should install the Verslagen head plug and cam chain tensioner...and the Sneezy clutch cam to make their bike more reliable.

Title: Re: Beefing up the Clutch Post by TheSneeze on 07/13/23 at 09:32:45 I am officially out of stock.  I am heading over to my manufacture's place this morning to get another run started.  I will post up a new thread when I get the next batch completed.  Thanks for the support, guys!  I am really happy I could come up with an improved part the helps keep your Savages alive. EDIT - I actually have two left (my mistake).  I should have the new batch within two weeks.

Title: Re: Beefing up the Clutch Post by TheSneeze on 08/14/23 at 16:31:27 I have been away on a trip for the last 2-1/2 weeks. The new batch should be in my hands in the next week or so.  The current on hand quantity is still two.

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