SuzukiSavage.com /cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Evolution of a Hotrod Part 10 - Long Term Test /cgi-bin/YaBB.pl?num=1645499584 Message started by DragBikeMike on 02/21/22 at 19:13:04

Title: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:13:04 This is the tenth in a series of reports intended to document the results of progressive modifications to the LS650 engine. Part 1 Stock: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1620523526 Part 2 Airbox: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1621150483 Part 3 Exhaust: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1623048749 Part 4 Carburetor: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1625732492 Part 5 Cam: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1626391255 Part 6 Flywheel: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1626921647 Part 7 Head: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1627891507 Part 8 Compression: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1631491370 Part 9 Displacement: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1633054879 You can use this summary to navigate to any particular mods you might be interested in. What I described in parts 1 through 9 worked good for me.  If you decide to try this stuff on your own, you assume responsibility for the outcome.  If you don’t have the skills, don’t do it.  If you don’t understand something, STOP and get help.  Get a manual.  Read up.  Comply with ALL the safety requirements outlined in the manual.  Make sure you know what you are doing before attempting any of these modifications.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:14:55 At the conclusion of Part 9, we had a 692cc high compression engine.  It had a high-flow K&N air filter, high-flow 38mm carb, ported head, DR650 cam, high flow exhaust system, and a lightened flywheel.  The Wiseco 97mm flat-top piston increased displacement by 40 ccs, compression by about 3 points (8.5:1 up to 11.4:1) and tightened the quench clearance to .040”.  To hold the power, it needed a beefed-up clutch.  It ran great.  Tons of power, excellent fuel economy, and cooler operating temps.   I wanted to put some miles on it before I wrote the final report.  So, once the Big Bore Flat-Top had 6200 miles on it, I changed the oil & filter (3rd oil change), checked chain tensioner extension (14.4 mm), adjusted the valves (.007” as-found), cleaned the air filter, checked compression (225 psi) and started writing.   But something wasn’t right.  After a few miles, the vibration and audible noise seemed higher, the clutch felt like it was slipping, and the oil got black. When I did the service at 6200 miles, I changed out the oil drain plug.  I had been running the old-style non-magnetic plug.  I had a newer magnetic drain plug, so I installed it.  No particular reason, it just seemed like a good idea.  So now I had like 50 miles or so on a fresh oil charge, and the engine was noisy, and things seemed to be shakin more, and the oil was black already.  Best take a look. Oh my!  That’s not good. 8/25/23  As it turns out, I believe these chips came from the LH main bearing.  At first I suspected the chips were from the failed 5th gear, but later on I discovered that the main bearing had also failed. I simply missed the bearing failure.  DBM

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:16:09 Where did all those chunks of metal come from?  Would I have found even more chips had I been running the magnetic drain plug all along?  Why the heck was it shakin?  What’s with the clutch?  Why was the oil so black?   It seemed prudent to inspect the clutch.  I popped off the clutch cover to check things out.  The clutch was ace.  All the plates (fiber & steel) met new specs.  The springs had the same force as they had when I installed them.  No discoloration.  No signs of overheating.  No scoring.  Release mechanism was fine. Primary drive gears looked good.  No pitting.  No broken teeth. Cam chain tensioner was right where I left it, 14.4 mm. The lions share of the audible noise seemed to be coming from the alternator area.  I removed the alternator cover.  The alternator rotor had black sludge accumulation distributed evenly around the interior of the rotor, and a few metal chips here and there.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:16:55 Since it’s magnetic, the sludge was very hard to remove.  Wiping with a towel gathered some nasty black stuff, but I couldn’t get it all.  The magnets refused to let go.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:18:26 I yanked up & down on the alternator rotor and there was some loud clunking.  I knew the left-hand main bearing was a large roller bearing, but I didn’t think it should have enough clearance to permit that much movement, not enough to clunk.  There’s no spec in the FSM or Clymer’s. Time for a dial indicator check.   I removed the rotor and set up an indicator.  I could move the crankshaft up & down about .0035”.  That seemed like a lot.  I checked the same bearing on my spare engine, and it moved .0020”.  It also clunked but not as loud.  So, the left-hand main bearing on the engine in the bike had almost twice as much clearance as the same bearing on the spare engine.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:19:44 I did a cursory check of left-hand crank runout.  Cursory because it’s almost impossible to get an accurate runout, other things are moving the crank around.  The cam chain is tugging on the right-hand side, and the rod is pushing and pulling on the crank pin.  I figured it wouldn’t hurt to take a runout.  The runout was .0040” TIR.  The runout spec in the manual is .0020” TIR, but that’s checked with the crank assembly on V-blocks.  I set the indicator up to check axial play.   The crank moved to the right +.0020”.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:20:20 And the crank moved to the left -.0010”.  That’s a total of .0030” axial movement.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:21:25 I checked axial play on the spare engine crank, and it was only .0005”.  That seemed more like it.  The manuals don’t provide a specification for axial play, but .0030” seemed like it was excessive, especially when compared to the spare engine. I wanted to see how the transmission bearings were, so I checked the input shaft and the output shaft.  The input shaft had .0000” up & down, but .0022” axial play.  The input shaft on the spare was tighter, up & down was the same, but axial was only .0010”.   Comparison of the output shafts showed similar results.  The output shaft was .0010” up & down while the spare engine was .0000”.  The axial movement on the output shaft was a whopping .0050” while the spare output axial play was only .0010”. It was obvious that the engine in the bike was way looser than the spare engine.  I have no idea how many miles are on the spare, or how it was treated before I got my hands on it.  I have only logged about 1500 miles on the spare.  That was on the 97mm Pop-Top project.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:22:11 I removed the drive pulley from the output shaft.  The nut was super-tight.  To my surprise, there was a bright orange layer of corrosion on the splines, typical of fretting corrosion. Note that only the splines have the red deposits.  There hasn’t been any water on this pulley.  I don’t wash my bike, I wipe it down, and I rarely ride in rain.  When there is inclement weather, the pulley is rotating at high speed.  No water is getting into that joint.  Only the areas subjected to extreme contact pressure have the red rust deposits.  Looks like I caught this in time.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:22:52 Similar deposits were on the output shaft splines.  Don’t worry, I didn’t check axial play with the pulley removed, I just wanted to see if it made a difference.  It does.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:23:49 So, I have this noisy/shaky engine full of metal chips.  All the bearings are loose as a goose.  The crank seems to have excessive runout.  The clutch appeared to be slipping and the oil was black, but all the clutch components were within specs.  Hmmmmm? Could the rod bearing be in the toilet, or the wrist pin, or the piston skirt.  Time to pop the cylinder off. My beautiful new 97mm flat-top had a gouge in the skirt, and what looked like a chunk of black metal embedded.  The skirt was also peppered with all sorts of dings.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:24:27 The top ring looked terrible.  I’m used to seeing a nice, uniform polish 360° around.  This thing looked like it had been through a meat grinder.  That might explain why the compression was down about 15 psi.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:25:23 The 97mm cylinder was toast.  Several deep gouges ran through the lower two-thirds of the bore.  It’s a boat anchor, no more bore jobs on a 97.  Look at the finish on that thing.  It was running perfect until this happened, but what is “this”???  Note that the gouges are confined to the areas in the lower two-thirds of the bore.  I’m thinkin whatever did this came from the crankcase area, not the combustion area.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:25:57 The combustion chamber and piston top looked fine.  It wasn’t detonation.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:26:28 The piston top had almost no carbon accumulation, and the little that had accumulated came right off.  Also, no sign of detonation.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:26:59 The underside of the piston was bright and shiny, no varnish or discoloration.  This thing runs cool.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:27:54 What about the rod bearing?  That certainly could throw lots of metal debris right into the cylinder and also explain the noise and black oil and vibration.  I did the swing check discussed in the service manual.  It was .012” on the failed engine and .019” on the spare engine.  The FSM specifies a wear limit of .12”.  I was way below that.  The rod bearing turned smooth with no evidence of brinelling or powdering. The rod swung to the left -.006”.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:28:27 And the rod swung to the right +.006” for a total of .012”.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:29:06 I verified side clearance with a .018” feeler gage.  The spec is .004” to .026”, wear limit is .039”.  No problem with side clearance.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:29:34 Looked like the rod was fine.  Not a whole lot more to choose from.  Gotta be one of the ball/roller bearings or the transmission.  When I rotated the input and output shafts, I could find spots where it would bind.  It took a significant amount of force to rotate the shafts by hand.  You can see all the input gears through the opening in the crankcase.  Might as well look.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:30:14 Well, I’ll be.   I have never trashed a transmission on a motorcycle.  I guess everything has its limit.  Looks like the limit on the Savage is fifth gear.  That sucker just couldn’t handle all those WOT runs in top gear.  The torque was simply too much for the gears to handle.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:30:53 Sorry, my pictures aren’t the best.  More to come once I get it opened up.  I’m dying to see what the output gear looks like. Here’s another shot of the input gear.  You can really get a feel for the depth of the pits from this shot.  The left side of each tooth is really cratered.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:31:29 This is a picture of an output gear.  It’s fifth gear on the output shaft of a spare transmission that I have.  Note how the crest of each tooth has been beveled.  That effectively reduces the load bearing surface of the gear tooth.  It shifts more load to the other side of the tooth.  The pitting on my input gear is confined to the same side of the tooth.  I’m thinkin a four-speed gear set might be a better option for high output engines.  Top gear on the four-speed trans is wider and doesn’t utilize a bevel.  It can probably handle more torque.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 02/21/22 at 19:33:29 Does this mean we should be wary of the 97mm flat-top piston mod?  I don’t think so.  You must consider what I have been doing to this thing.  The bike has a little over 25,000 miles on it.  Of those 25,000 miles, about 1,500 were logged with the spare engine.  The remaining 23,500 miles were logged on the current bottom end & transmission.  Most of those 23,500 miles were logged beating the crap out of it.  All sorts of crazy engine combinations.  Hundreds of WOT pulls.  A whole bunch of LSR runs.  Countless hours spent cruising at 4500 to 5000 rpm.  Repeated trips to 7500 rpm, over & over & over & over.  This baby is my test lab.  Its sole purpose is to develop and test modifications.  Failure was inevitable. Fast 650 thought it would be the engine case (I fooled him).  I personally thought it would be the rod, or an exhaust valve.  “IF” I had been running a magnetic drain plug, I might have caught the problem in the early stages of failure.  Maybe I would not have ruined the cylinder.  Lesson learned. Once I get it all apart, I will put the crank between centers and do a proper runout check.  I’m hoping it is not tweaked, but if it is, it will be a good opportunity to learn about truing a crankshaft. I’m guessing fifth gear has been goin in the potty for a long time, probably started when I did the first tight-quench mod in 2019.  That bad-boy failed at WOT in fifth gear.  Insufficient ring gap.  Pretty ugly.  Maybe the pitting in the gear teeth started with that setup.  It had a lot of compression and made about 42 HP.  I rinsed out the bottom end with clean oil, installed a new cylinder with a Wiseco pop-top, and forged ahead. The fretting on the output splines is superficial.  It cleaned up nicely.  I’ve been reading up on spline fretting and all the literature seems to point to lubrication.  So, I’m gonna start painting my splines with moly lube when I install the pulley.  Not the threads, just the splines. I’ve got several things I want to test, so to keep the program going I installed the spare engine.  It’s set up with a 94mm flat-top, DR650 cam, and Stage II cylinder head.  It runs great.  The clutch is fine, no slippage, good lever action.  To smooth out power delivery, I installed the stock flywheel.  Any WOT work above 5000 rpm will be reserved for the lower four gears.  I’ll be using fifth gear strictly for cruising. I plan to rebuild the 97 mm flat-top using a four-speed transmission.  Since I have two 97mm pop-top pistons, I want to see if I can turn one of those into a flat-top piston and adjust the cylinder height to achieve reasonable quench and about 10.5:1 compression.  That looks like it will be a lot of fun.  The transmission conversion will certainly be interesting. This concludes the project.   I hope some of you found my reports informative and can use the data I collected to help make decisions on your own project.  I think the final configuration with the 97 mm flat-top piston is a good setup as long as you exercise prudent use of the throttle in fifth gear.  It’s a blast to ride. Best regards, Mike

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by TheSneeze on 02/21/22 at 23:35:39 Outstanding write up, Mike!

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by LANCER on 02/22/22 at 09:29:57 An interesting report, thank you Mike.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by Armen on 02/22/22 at 20:58:59 Wow. Thanks for sharing. A few things… I always put Anti-Sieze on the splines. And green Loctite on the threads. I had an XL250 Honda a million years ago. I tweaked it six ways from Sunday-carb, pipe, cam, ported head with O/S valves with HD springs, bored, hi compression piston, etc. Ran like a beast until the main bearings blew their lunch. You find your limits by going over them….

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:08:14 4/17/22  Teardown Inspection Results Now I have the engine completely disassembled and have finished inspecting everything.  I wanted to share what I found and offer my assessment.  I’m not an engineer or a metallurgist, and I don’t have a materials lab, so the comments are simply my opinion. Before splitting the case, I used a magnet to fish around in the pool of oil directly below the input gears.  There were plenty of metal flakes in there. 5/7/22:  Boy did I mess this up.  Sorry, I forgot to paste in the text associated with the picture.  Never too late to patch it up.  This text was supposed to be in the original reply. I got the cases split and immediately threw the crank shaft between centers.  I was worried that it might be tweaked.  It looks great, but centers don’t lie. My initial assessment was correct.  It’s running out .004” TIR with the plus (+) directly opposite the crank pin.  That confirms that the webs are spread.    Fortunately, it’s not twisted.  I might be able to straighten it.  Time to learn something new.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:09:34 My next concern is the left-hand main roller bearing.  That thing seems to have a lot more play than it should.  From the outside, it looks good, but there was a lot of up & down play. 8/25/23  Although the LH main bearing looked fine, it had actually failed.  The inner race was severely spalled.  Even with the spalling, it turned smooth.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:10:20 The rollers look a bit scored but overall seem to be in decent shape. 8/25/23  The inner race had failed, but you can't see the inner race unless you cut the bearing apart.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:11:09 The left-hand main bearing outer race doesn’t look too bad either. 8/25/23  Yes, the outer race looked great, but the inner race had severely spalled.  If I had been smart, I would have cut the roller assembly open and looked at the inner race too.  Who would think that the inner race would fail without chewing up the outer race.  DBM

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:12:30 I removed the left-hand main bearing outer race.  The bearing bore in the case has some very unusual defects.  I’ve never seen this before. Have any of you ever seen anything like this? Totally weird.  It’s definitely not a crack.  You can clearly see the bottom of the defect.  Something has been going on here.  BTW, that’s a steel insert that has been cast into the aluminum case.  They did a beautiful job of casting the aluminum around the insert.  If it hadn’t started to flash-rust, I probably would have never noticed the steel insert. 8/25/23   I think this was caused by the outer race turning in the bore.  The inner race had failed and I suspect that it would grab the rollers and cause the bearing to bind up at speed.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:13:35 Another unusual problem is defects all around the shoulder in the bearing bore.  You can see from the prior picture that from the outside of the case, the left-hand main bearing looks fine.  But look at the shoulder.  It’s all dinged up.  I don’t beat bearings out.  I use bearing jacks.  The outer race was removed with great care.  No beating with a hammer and punch.  It was removed with a nice even draw using a jacking tool.  Nothing contacted this shoulder when I removed the outer race.  Where did these dings come from? Ugly!  Any of you ever see anything like this? 8/25/23  Since the only way this could happen is for the outer race to move axially such that debris from the failing inner race could get lodged between the case and outer race.  Again, the outer race had to be moving around.  DBM

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:14:33 Looking at the outer race I don’t see any clues.  Something tore up the shoulder in the left-hand main bearing bore, but it wasn’t the outer race and there are no indications that the outer race was turning in the case.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:15:44 The rollers look good too.  No evidence of chipping or debris.  Nothing that would explain all the damage in the adjacent case material. 8/25/23   Yes, the rollers looked fine, but how did the inner race look.  You can't see the inner race unless you cut the cage and peel it open.  Why didn't I do that???  DBM

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:17:24 The case bore for the right-side main bearing has some unusual indications too.  These indications don’t look anything like the left side main bearing bore.  Again, I have no idea what these marks are all about.  Any of you ever seen anything like this? I found some literature on the internet that suggest tracks like this are caused by vibration.    I guess they could be the results of vibration.   The excessive crankshaft runout certainly caused a lot of vibration, and I’ve been running pistons that were significantly heavier or lighter than stock (that didn’t help).

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:18:19 The right-hand main bearing is also a bit loose in the case.  You can insert it into the bore about one-half before it starts to engage interference.  I’m not likin that.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:19:08 The spacer that resides behind the drive pulley looks unusual.  There is a ridge around the circumference of the face that bears against the inner race of the output shaft bearing.  I wasn’t sure if that was normal, so I asked Dave if he had any spacers to inspect.  Dave’s spacers don’t have a ridge.  Then I found some spacers in my junk and none of them have the ridge.  Looks like the output shaft has been flexing and the resultant cyclic stress is causing the spacer face to fret away.  The ridge is formed because the inner race of the bearing has a large radius, so the spacer doesn’t contact there.  As Armen says, “you find your limits by exceeding them”.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:19:47 The spacer is worn about .006”.  I’m amazed that I found the pulley nut super-tight.  Maybe I was just fighting the Loctite to get that nut off, but the pulley seemed tight too.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:20:42 You can see that the inner race of the left-hand output bearing also shows signs of fretting.  Also note that the bearing is sealed.  That’s an important feature.  The seal forces the pressurized oil to go through the hollow output shaft rather than just dribble through the ball bearing.  That oil lubricates the gears that run on the output shaft.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:21:22 The two left-hand transmission bearings (input & output) look like regular bearings when viewed from inside the case.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:22:00 But once the bearings are removed, you will see that each has a seal on the outboard side of the bearing.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:22:52 Here you can see the oil feed hole for the left-hand input shaft bearing bore.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:23:28 And this is the oil feed hole for the left-hand output shaft bearing bore.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:24:17 It’s important to understand the role that the bearing seals play.  Install bearings without seals and you eliminate the oil supply to the shafts and gears.  This oil does not lubricate the gear teeth, it lubricates the bore of the gear.  No oil and the gear will eventually lock up on the shaft.  Very bad for shifting and fuel economy.   It’s also important to understand that the little o-ring on the clutch release push-piece is an important part of the transmission lubrication system.  Leave out that o-ring and it will bleed off oil intended for the gears.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:24:56 First gear on the input shaft had some fretting.  Looked like early stages, probably no harm done.  Same issue as the output shaft pulley spacer and bearing.  The shaft is probably flexing under extreme load and subjecting the faces of the gear and inner race of the ball bearing to cyclic stress.  Each rotation of the shaft cycles the load one time.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:25:54 This is the input shaft right-side bearing.  You can see the fretting on the inner race.  Also note the lengths Suzuki has gone to prevent the outer race from moving.  It has an anti-rotation pin plus a retainer plate.  I think the retainer plate’s primary mission is to lock the bearing axially.  It must handle thrust load off the helical primary gears.  This bearing was very difficult to jack out of the case.  It took a lot of force.  The right-side input bearing might be prone to spinning in the case.  Be careful with this bearing.  It also costs a fortune (about $75 bucks).

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:27:00 Going to a bearing supply house for replacements might be a crap shoot.  I don’t think you will be able to find an off-the-shelf replacement for the right-side input shaft bearing.  That special anti-rotation pin might prove problematic.  The only bearing that had markings that could be viewed without removal was the right-side output shaft bearing.  It was clearly marked 6004-C3, indicating it has increased clearance intended for operation up to 248°F and/or has an interference fit on both the inner and outer races.  The others had no markings at all, or no clearance designator.  I am working on trying to check clearance so I can try to correlate to a designator. The right-side output shaft bearing is the only one with comprehensive markings that can be viewed without removing the bearing.  If this bearing is representative of the other bearings, it implies that I should be looking for bearings with C3 clearance.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:27:38 Right-side main bearing, no markings anywhere.  I get that I could simply measure the thing and go buy a 6207 bearing, but I need to know what clearance the designers intended (C1 through C5).  I think that’s important.  More to come.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:28:25 I expected to find a lot of metal debris in the oil pump suction strainer, but it only had soft junk in there.  Mostly sealant particles and a few aluminum chips.  I guess that’s good.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:29:49 I’m paranoid about balance shaft timing.  Recent reports from other forum members have shown ugly catastrophic failures caused by collisions between the rod and the balance shaft weight.  The only way that can happen is if the balance shaft timing gets out of whack.   For timing to shift, there must be a problem with the drive pin, drive key, or the cushioning springs. Since my current problem manifested through noise & vibration, it stands to reason that I should be checking out the balance shaft system. The balance shaft drive gear looks OK.  The teeth are not as smooth as I would like, but there isn’t anything ugly goin on.  The critical drive pin is tight and positioned where it’s supposed to be.   It hasn’t moved.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:30:27 The balance shaft driven gear looks similar to the drive gear.  The teeth are not pristine, but they look OK.  All the springs are in place and look fine.  Same goes for three pins captured in the springs.  The pins serve as hard stops.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:31:03 The balance shaft drive key is in good condition.  It’s tight and there are no signs of deformation or shearing.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:32:06 I was surprised to find fifth gear on the output shaft in good shape.  No pitting at all.  Another mystery.  How the heck can the input gear be all cratered out without wrecking up the output gear?  That relief/bevel on the crest of each tooth is not doin me any favors.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:32:55 Just look at the pits in the input gear.  A little more and I bet a tooth would have snapped off.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:34:18 I think an old four-speed gear set might solve the problem.  The late-model fifth gear is on the right and the early model fourth-gear (top gear) is on the left.  The four-speed definitely has beefier input gears.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:34:58 This shows the output gears for a 4-speed and a 5-speed.  The 4-speed top gear is on the left.  The 5-speed top gear is on the right.  Top gear on the 4-speed looks a lot beefier to me.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:36:14 That’s about all of it.  Nothing outright failed, but the input 5th gear was getting close, and the debris wrecked my cylinder.  I could probably hone the cylinder to clean up the raised material, but it would never be the same.  It would run OK, but I’m not lookin for just OK. The plan:   Get the crank squared away so that the runout is within spec. Change out the bearings to get rid of the excessive play.   Use Loctite retaining compound on the main bearings.  That should mitigate the case bore issues. Try to install a four-speed gear set to take advantage of the beefier gears. Bore out my old tight-quench cylinder to 97mm.  It’s about 3mm shorter than stock so the new 97mm flat-top piston won’t work with it. Modify a 97mm Wiseco pop-top to work with the shorter cylinder.  Make the pop-top a flat-top and try to find a way to adjust the piston assembly weight to match the stock assembly.  Target CR about 10.5:1 to 11:1. Assemble the stage 3 head with a DR650 cam and stock valve springs.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:38:39 I’m currently running my spare engine that is set up with a 94mm flat-top Wiseco.  It’s running great and I intend to run it for a long time.  I’ve logged 3974 miles on it so far.  I want to do a long-term test on the flat-top piston.  I tore down the original 94mm flat-top engine when I started my Evolution of a HotRod project.  At that time, the 94mm flat-top had 2249 miles on it.  Add the additional 3974 miles from this current setup and the piston and rings have run 6223 miles.  So far so good.   When I reassembled the current engine, I just used the original 94mm flat-top and the cylinder it was running in.  I used the old rings over.  The Web 340b cam I had been running was pitted pretty bad, so I simply replaced it with my trusty old DR650 cam.  I left the heavy-duty RD springs and retainers alone (too lazy to change them).  The long-term test will provide an opportunity to see how the DR cam handles heavier springs. So, I will continue to run the 94mm flat-top engine while I work on the Big Bore 4-Speed project.  I want to put 10,000 miles on it and then tear it down and report.  The focus will be the piston, rings, and cylinder to assess how the special piston holds up. Regarding the transmission failure and the unusual bearing seats in the engine case, I solicit your input. Have any of you seen the unusual fretting, tracking, chatter marks, dings, debris damage etc. that I show in my pictures of the main bearing bores?  If so, do you know what caused it?  How to fix it or prevent it? Have any of you used Loctite 609 or 620?  What was your experience with the product?  Did you have to take the bearing out later and how hard was it to get out? Have any of you experienced the tweaked crankshaft issue?  How did you deal with it? Have any of you had a pitting problem with 5th gear?  What can you share? Armen, throw me a bone.  What can you tell me about your Honda bearing failure?  Did the balls disintegrate?  Races spall?  Cages fall apart?  Outer races spin in the case?  How were the case bores?

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/06/22 at 20:39:30 I hope some of you find this report helpful.  As always, I welcome your comments.  I plan to do a report on the Big Bore 4-speed engine.  It’s a good project and I’m sure I will learn a lot. Best regards, Mike

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by TheSneeze on 05/06/22 at 22:27:22 Coming from a career in quality assurance and inspection, I admire your observation abilities.  Good write up, Mike!

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by Armen on 05/07/22 at 01:47:41 Hey Mike, As always, thanks for the thorough documentation and analysis. I’m hoping work starts on my other garage building in June, so that I can bring the Savage here and get it on the road. Currently it lives 2 hours away. It’ll prob be in the high 30 HP range, so hopefully not frag the way yours did. When we were racing a 250 Bultaco and an SR500 Yamaha, I had those motors apart a lot. More so the Bulto, of course. By the time it was done, it made roghly double the stock HP, so parts wore out in a hurry. I used Loctite on the main bearings into the cases. That was long ago, but I don’t think I used Green sleeve and bushing mount, as I never would have gotten the cases apart. I’ve def used green Loctite on bearings with a loose fit where it was the only way to save the fit without doing a bore/sleeve operation. When my XL250 Honda puked, I believe it was balls/races. That was 40 years ago, so memories are a bit thin. I didn’t fix it, just sold it as a basket case. The Bulto was born with ball bearings on both sides. I swapped to a roller bearing on the right (drive) side and used a balll bearing on the left to keep the crank in place. BMW used a f*g barrel roller bearing on rear of the crank on their higher output R69S in the 1960s. Norton used a roller bearing on the cranks of the later big twins after massive crank bearing failures. It was  a Superblend, and I believe it had a slight barrel shape to the rollers. IIRC, the Norton cranks would flex something like 13 degrees off centerline at redline, The ball bearings couldn’t take that kind of off center load and blew their lunch. I’d def take the oil pump apart on yours and look for scoring. As little fun as it is, I’d prob press the crank apart and check the big end pin for scoring. One thing I do on BMW trans rebuilds is take a gunsmithing brass bore brush, put it on a cordless drill, and run it through the trans shafts. Lots of caked on swarf in there that wants to come loose in a nice hot oil bath.  I’m assuming the Savage trans shafts are hollow for oil flow, so I wonder if this can be done? I have a magnetic drain plug in my Savage. I used to rip apart the paper oil filters on bikes that I was worried about to look for debris. Again, thanks for all your hard work and great documentation! Can’t wait to see the next installment.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 05/08/22 at 01:45:46 Thanks Sneezy & Arlen.  It's a fun project.  Too interesting, have to share. Once the oil pump is removed from the case, you can see inside.  The gerotor looks fine.  No debris in the filter.  The suction screen on the pump is really a fine mesh.  I guess it did the trick.  Also, no evidence of debris anywhere downstream of the pump suction strainer.  Looks like I caught a break. At this point, I'm mostly concerned about the bearing bores in the case.  I believe the Loctite 620 will do the trick.  Based on the condition of the bearings (races and rolling elements), I don't think I will be removing the new ones for a very long time.  That assumes no more gear failures. Good tip on brushing the bores of the transmission shafts.  I can do that on the input shaft.  The output shaft is closed on each end.  Right side has the speedo drive incorporated.  Left side has a plug.  I don't wanna mess with that plug.  Have to cross my fingers.

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by Theduderino on 06/11/22 at 22:08:20 Thank you for taking the time. It is greatly appreciated. Nicely done sir

Title: Re: Evolution of a Hotrod Part 10 - Long Term Test Post by DragBikeMike on 08/25/23 at 16:19:02 It turns out two things had failed.  The obvious item was fifth gear, which was very easy to see.  The not so obvious thing was the left-hand main bearing. The failure was hidden beneath the rollers and cage.  You can't see the inner race unless you cut through the cage and peel it away.  I believe the bearing failed due to lack of lubrication.  I always thought that the oil holes in the cam lobes were there to provide lubrication for the cam and rocker arm cam followers.  But the DR cam always looked great.  The reservoir below the cam seemed to provide adequate lube, even when I ran those super-beefy RD springs.  But it turns out those holes in the cam lobes are needed to throw oil forward into the exhaust valve spring pocket.  That oil then runs down the forward drain to provide lubrication for the left-hand main bearing.  Too much power and not enough oil, a bad combination. If you are running a DR cam, drill the holes, or you will end up with one of these.

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