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Message started by BlakeEM on 06/27/20 at 14:49:42

Title: s40 major failure, balancer hitting case, cause?
Post by BlakeEM on 06/27/20 at 14:49:42

My wife's little 2006 Suzuki s40 was making a "tapping" sound when exiting the freeway and then the balancer shot out the front of the engine onto the road. :o

At first I thought it was the cam chain tensioner failing but this was fine. It still has compression, shifts through all the gears, nothing blue/golden from heat, and everything has plenty of oil.

The bearings seem perfectly fine and turn smoothly on the balancer. It appears that it was contacting the front of the case based on the scoring on the end of the balancer weight that you see in the photos along with the chip missing from the inside front of the case.

Anyone have any idea how this could have happened? Cam chain and guides were replaced a year ago and look in great shape.

https://imgur.com/MwrJ43F

https://imgur.com/m0KCLt7

https://imgur.com/tqU15gA

https://imgur.com/K7IIbHg

I'm thinking of getting a new case and swap everything over, however I first need to figure out how this could have happened so I can make sure it doesn't happen again, for that I need your help because I'm stumped!

Thanks!
-Blake

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 06/27/20 at 16:07:52

Thats the second one Ive seen in 15 years of being here. I wanna say it was Verslagen, but it coulda been another of the local bike geniuses.. I dont have the experience to gut a case and put all the goodies in another one.. Im pretty sure its above my paygrade. I would think gettin a used motor and stabbin it in there and riding would be a lot easier. Maybe even close on costs,,No gaskets, just slap it in,, well,, check the tensioner,, maybe a gasket gets dead there

Title: Re: s40 major failure, balancer hitting case, caus
Post by verslagen1 on 06/27/20 at 16:50:22

there has been 1 or 2 that have puked out the balancer, but not me.
mine crapped out a bearing, made a lot of noise, then I replaced the bearings.
the bearing cage gave up.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Ruttly on 06/27/20 at 16:50:29

That s.. next level failure , catastrophic ! Never seen that before. If I had to guess something passed inbetween the balancer and crank causing the blow out. You will have to be the detective on this one whatever it was may have been spit out on the road. When disassembling engine look for missing parts and fully inspect the gears that drive the balancer. I noticed a mark on the balancer like it hit something , a major clue !

Title: Re: s40 major failure, balancer hitting case, caus
Post by Ruttly on 06/27/20 at 17:12:12

I was going to remove the balancer on my next engine . Now I will be rethinking this idea.
That's one big hole.
I would just buy another engine after you find out what caused the failure.
Cheaper and quicker to get it back on the road.
Thanks for sharing your story & pictures.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/27/20 at 18:20:35

It sounds like a replacement engine is the way to go. I'll finish disassembling the lower end tomorrow and see if I find anything that came loose. I didn't notice anything missing in the top end and the oil/filter didn't have metal in it.

Time isn't an issue since she is working remote for a couple more months (this was her daily) so money is her main concern.

-Blake

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 06/27/20 at 18:38:11

Ohh,, I would Definitely autopsy that thing,, If the head and cylinder took no damage, you could stick an engine in the bike, and have the top end you have layin around modded, swap them in,,if shes into that kinda stuff,, or sell them to someone who wants to mod their bike without downing it for long,,

Title: Re: s40 major failure, balancer hitting case, caus
Post by Ruttly on 06/27/20 at 21:43:46

If by chance the timing between crank & balancer goes bad , the balancer weight will contact the connecting rod and that's how you get a crater in your main case. That explains any ticking or clunking sound prior to the eruption of internal engine parts onto the highway.
Sorry for all that but it is a epic story of a epic failure !
Glad she didn't get hurt.

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 06/28/20 at 02:32:37

y chance the timing between crank & balancer goes bad , the balancer weight will contact the connecting rod and that's how you get a crater in your main case.

But how does that timing change?
The marks inside the case?

What's the mileage on it?

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 06/28/20 at 03:50:16

Blake:

Wow.....that is a hard core engine esplosion! :o

That scuff mark on the balance shaft looks like it is in the right place for the lower end of the connecting rod to have smacked it......look for a similar scuff on the connecting rod or crankshaft.

The engine is 14 years old - the rubber parts are going to be aged even on a low mileage bike. When I rebuild and engine of this age I tend to replace all the seals and gaskets........you will probably spend a couple hundred dollars on those parts. There is also a problem right now with getting parts from suppliers - I waited 2 months for a set of fork protectors from Suzuki and finally gave up and cancelled the order.......evidently Covid19 has affected the shipping routes.

Since you have a good top end, maybe you could get by with finding a good bottom end. It does seem a shame when folks tear apart a healthy engine to sell for parts - but eBay sellers make more money selling an engine in parts than they do selling a complete engine. Parts are also far easier/cheaper to ship - a complete engine is large and heavy and expensive to ship.

Where do you live?

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 07:38:03

What could cause the timing to go off or would it have had to happen during assembly? It does sound like that could be the issue. The timing chain, tensioner, and gears all looked fine. I wasn't the one who replaced the timing chain and it ran fine for a year before this happened.

The engine has 28k miles on it.

I'll look for a mark on the connecting rod/crankshaft.

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 06/28/20 at 08:15:15

Shipping on an engine would get expensive,, BUT,, If you can find an engine in a direction ya mite wanna go spend a weekend, take a trip, you and the girl, and bring a motor home? Maybe?
Sure ,, thats gonna cost more than shipping,,but, ya Get more than a lump carried by someone else..

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 06/28/20 at 08:56:00

I don't believe the timing can change - the gears are pressed onto the crank and counterbalance shafts.

The only way I believe contact can occur in the location shown is if the bearings fail and allow movement of the rod, crank or counterbalance shaft.

The photos seem to show the rod hit the counterbalancer - and that pushed the counterbalancer hard enough to break the case at the bearings and shove everything out the front of the engine.

Title: Re: s40 major failure, balancer hitting case, caus
Post by srinath on 06/28/20 at 09:02:50

012F222826060E430 wrote:

That'll buff right out.

Shhhhheeeeesssshhhh I've seen chit like this on a GS500 - a bike that was about as well put together as a ball point pen …

Cool.
Srinath.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 09:37:59

Was definitely timing, just spun the crank and it was obvious.

How the hell did we not notice this? I'm going to have a good long talk with the shop.

https://imgur.com/vgNFuh4

https://imgur.com/nC3nvCT

Crazy! :(

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 06/28/20 at 11:19:04

I don't see how this could have been a timing issue between the crank and the balance shaft......as the timing can only change if the case had been split and the crank or balance shaft was removed and not installed correctly. The cases don't have to be split to change a cam timing chain and guides........find out if the shop split the case for some reason.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 14:58:18

I'm not sure what process they followed when they replaced the timing chain and guides. I've used the shop dozens of times however this was their first time working on this specific bike, usually they work on high performance stuff.

I do remember it had a rattle/ping sound but the exhaust was loud so it wasn't that noticeable. I was thinking that it was an exhaust leak since we had that issue in the past, same with the popping on deceleration. An exhaust leak changes with revs so I didn't think anything of it at the time.

@dave I'm in San Diego.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Zepp on 06/28/20 at 15:06:28

Im mostly on Daves side.. at least 99,99% the rest goes to aliens or some fabikation faliurs!

And I dont belive in Aliens.. but in any case, they have to ruin the bearings or crack the shaft befor it hit the case!
If the shaft is okey, then it is the bearings!

Title: Re: s40 major failure, balancer hitting case, caus
Post by Ruttly on 06/28/20 at 15:08:34

Yeah after seeing those marks on the balancer I kinda figured you would find a corresponding mark on the crank and/or the connecting rod. If your going to reuse these parts you will need to check to be sure balancer shaft is straight and true and crank halves are properly aligned and connecting rod isn't damaged. So new bike or new engine may be the way to go.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 06/28/20 at 15:25:10

4D636E646A4A420F0 wrote:

I assume the timing went off when they replaced the timing chain and guides.

@dave I'm in San Diego.

There are 2 things that need timed in this engine.

The camshaft needs to be timed when you replace anything related to the camshaft or cam chain. This would have been done when they replaced the cam chain and guides......you said the engine has compression and turns over fine - so I believe the cam timing is likely fine as it ran for a year after they worked on it.

The balance shaft needs to be timed if the center case was split and the balance shaft and/or crankshaft was removed. There is no reason for the shop to have split the center case into the left and right halves to replace the cam chain or chain guides.

Something went wrong, and at this point I don't believe it was the shop screwing up the timing......if they did I can't see why it would have taken a year for the collision between the rod and balance shaft.

This photo shows a nice even "squeeze" of sealer oozed out of the crank halves, and I believe this is the original factory applied sealant, as getting the sealer this even by hand would be difficult.
https://imgur.com/K7IIbHg

I asked where you are located so that we might be able to find you the engine or parts near you. My northern KY location puts me about as far away for shipping zones as we can get.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 16:56:41

I found another issue, it looks like the primary drive gear was scraping the case. What could cause this?

https://imgur.com/CCwkG9c

The crank shaft feels solid with no noticeable play. Same with the connecting rod and wrist pin.

What was the crankshaft/connecting rod making contact with? It looks like the balancer was hitting the front of the case and maybe the connecting rod, but what about the crankshaft? Where else should I be looking for damage? It got very hot so I'd expect to see more damage.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 17:18:40

I removed it and found more issues.

https://imgur.com/VzDZa9o

https://imgur.com/SXPtibU

Title: Re: s40 major failure, balancer hitting case, caus
Post by badwolf on 06/28/20 at 17:23:03

For the primary gear to rub on the case, either the case bent outward when it blew, or the main bearings on the crank are shot, allowing the crank to move like it ain't spose to.
Have you checked the crank bearings? If they went bad that would allow the crank to hit the counterbalancer.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 17:24:04

Wow!!!! :o

Blake, I am so glad your wife is OK. That could have been a really bad event if it had failed on the freeway.

I agree, the only way the rod could have contacted the balancer weight in that particular location (the lower and deeper rub on your photo) would be for it to be out-of-time with the crankshaft.

A bearing failure might have resulted in the upper rub, but the lower (and deeper) rub had to be timing.

Title: Re: s40 major failure, balancer hitting case, caus
Post by badwolf on 06/28/20 at 17:25:22

Yea, your crank is moving sideways! If it moved enough the gears may have jumped a tooth or more.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 17:28:13

This picture shows the con rod approaching the balancer weight. While the rod is moving toward the weight, the weight is moving away from the rod. This is the only position where the rod could conceivably line up with the portion of the weight that has the heavy rub. In this position, there's like over an inch of clearance between the rod & weight.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 17:32:05

As the crank continues to rotate, the rod moves forward but the weight is moving away from the rod. When timed properly, there is still at least one-half inch clearance between the rod and weight. And the surface on your weight that has the heavy rub no longer aligns with the rod. Even if a bearing was bad I don't think the rod could have contacted the weight in your heavy rub location.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 17:32:46

The crankshaft turns smooth with no free-play and the bearings aren't making any sound like I'd expect if they were bad. I'll check them more closely once I get the crankshaft out.

If the crankshaft was only contacting the balancer why isn't the balancer discolored from heat like the crankshaft?

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 17:33:39

Under normal circumstances, even at the closest proximity there is still at least one-quarter inch clearance between the rod & weight.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 17:41:35

Could an over tightened primary drive gear cause this and shift the crankshaft to the side so that it skips gears causing the balancer timing to be off?

https://imgur.com/SXPtibU

You guys are awesome, thanks for all the help and pictures! It's taking me a while to disassemble since I need to keep taking breaks to read the Clymer manual so that I know what I'm doing.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 17:42:34

All that being said, I would not be so quick to blame this failure on the shop that replaced your timing chain.

Let's face it, if the dealer had split the case (highly unlikely) and reassembled with the balance weight out-of-time, the engine would have vibrated terribly. Like you would hardly be able to hold on to the handlebars. In addition, the contact between the rod and balance weight would have been present from the day you picked the bike up from the shop. That knock would have been so obnoxious you would have never accepted the bike. You would have insisted they correct the issue. It would have been unmistakeable. Klunck, Klunck, Klunck……

However, it is possible that the timing key or timing pin may have sheared, allowing the drive gears to loose control of the balance weight relation to the crankshaft.

Check the timing key on the driven gear. Remove the gear from the shaft and make shure the key is not sheared off. Don't rely on a visual of the end of the key. Take the gear off and inspect the whole key.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 17:49:21

If the driven gear key is all in one piece, it might be an issue with the drive gear pin. You normally would have to split the crankcase to inspect the drive pin, but you may be able to check it to see if it is correctly locked to the crankshaft.

Start by breaking loose the primary drive gear nut (LH threads) on the end of the crankshaft. Then see if you can rotate the timing gear independently of the crank. If that gear turns independent of the crank then the pin is either missing, backed out, or sheared.

This is the pin in question. It engages a hole in the crank.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dennisgb on 06/28/20 at 17:58:42

When looking at all the pictures it looks like a bearing failure.

I had a Yamaha Raptor 660 that I bought cheap from a guy who said the rod had gone. One of those deals where you spend a bunch of time trying to figure out someone else’s screw ups. I put a battery in it and hit the starter...bang! After much screwing around I found the guy replaced the clutch and put the balance shaft in off time. I set the timing marks and put it back together and it started right up. So I have a case where someone mucked up the timing of a balancer. Difference is that one came out without splitting the case

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 18:01:09

@DragBikeMike I'll check for that pin now.

I split the case noticed more damage to the crankshaft. I'm not sure where this was rubbing.

https://imgur.com/wKSoEe0

https://imgur.com/ePlbJVI

https://imgur.com/tMkyV3f

inside of the case.

https://imgur.com/HBv92IH

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 18:04:03

It is possible that the rod bearing failed which resulted in the light contact (upper rub in your picture). That light contact may have caused the drive key or pin to shear. Then all hell broke loose. Check the rod bearing by rotating your crankshaft while observing the rod through your new inspection port. You should be able to easily tell if the rod has excessive play.

It is also possible that the bolt that secures the balance shaft to the right hand bearing was loose. That would make the key carry all the load. Over time, the heavy weight spinning, accelerating, decelerating would shear the key.

It is also possible that the shop did not properly tighten the nut that secures the primary drive gear. That nut pinches the primary drive gear, cam chain sprocket, main bearing inner race, and the balance shaft drive gear. If the balance shaft drive gear is not pinched, the drive pin has to carry all the load. Same issue as the key. Accelerating, decelerating, back & forth, eventually the pin shears.

Check your rod bearing for play. Check the balance shaft bolt and the primary drive gear nut. Check the key and the pin. Also, look over the springs in your balance shaft driven gear. Makes sure none are missing or broken. Tell us what you find.

This is a very serious failure. It could have been terrible. We could all use a lesson on this.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 18:19:00

Here is the pin in the balancer. It's barely hanging on, I can't remove the washer.

https://imgur.com/qquyZYm

https://imgur.com/VEBUgRo

https://imgur.com/F7ldFCB

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 18:23:08

Hey Blake. What is this? Could it be the drive pin for the balancer drive gear? This is a blowup of your picture. It looks like the drive pin is coming out through the hole in the crank.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 18:29:14

@DragBikeMike It was a pin in the crankshaft, it fell out when I was disassembling. I have no idea what was holding it in or what it's for. It seemed strange that it fell right out before I even split the case.

There is no noticeable freeplay side to side or up and down in the connecting rod. It spins freely however I expected there to be a little bit based on what I've seen on other bikes.

Title: Re: s40 major failure, balancer hitting case, caus
Post by badwolf on 06/28/20 at 18:30:12

The drive gear on the crank for the counterbalncer is just PINNED in place, not on a spline? That is asking for trouble!
Not like the Suzuki engneers, they normaly are a sharp bunch.
But after over 30 years of production, I guess anything can happen at least once.

Title: Re: s40 major failure, balancer hitting case, caus
Post by badwolf on 06/28/20 at 18:37:03

That ''pin'' in the balncer is a key, not a pin.
And it is halfway sheared! That would throw things out of time.
Question is, did it cause the problem, or was it caused by the problem?
I have only seen that happen on a lawnmower when it hits a BIG rock and stops instantly.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/28/20 at 18:37:23

Wow!!!!! Those pictures of the drive key are eye openers.

Please let us know about the drive pin too. It might be an optical illusion but sure looks to me like it's coming out of the hole in the crank. If it is the pin coming out of the hole, I'm gonna guess that the pin backed out, resulting in the drive gear slipping, resulting in the rod contacting the weight, resulting in the key almost shearing and the case blowing out.

Thanks so much for posting these amazing pictures. The details are outstanding. This is some very valuable information. I think we all need to keep an eye on these drive keys and pins. That pin needs to be captivated somehow. As a minimum, the primary drive nut needs to be torqued properly and checked periodically.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/28/20 at 18:48:35

Here is that drive pin. It looks like it's just pressed fit into the gear and it was definitely loose.

https://imgur.com/eupase9

Title: Re: s40 major failure, balancer hitting case, caus
Post by Ruttly on 06/28/20 at 20:32:17

What do you mean ? Your doing a great job . And the pics are great. Everything on that side is held tight by the nut , if overtightened the cam chain drive sprocket will shatter( trust me on that one ) letting the pressure on the nut go away, further letting balance drive gear to work back n fourth till the pin came loose slipped out and hit balancer weight. BAM ,end of story. So if that is the chain of events then the last one to torque that nut would be to blame. But your screwed unless it just came out of the shop recently. Welcome to SS , even if the circumstances do suck.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 06/29/20 at 09:49:53

Here is what I believe happened:

The flange broke off the back of the sprocket that goes on the crankshaft and holds the primary gear.
https://imgur.com/SXPtibU

This flange holds the crankshaft securely into the right side ball bearing, and prevents the crank from moving sideways. Once this flange broke off, the crankshaft could move to the left side.....as evidenced by the primary gear rubbing on the case. When the crankshaft moved to the left, at some point the right side of the crankshaft counterweight started to hit the counterbalancer shaft (ticking noise)....and at some point it wacked the counterbalancer hard enough to break the case and push the counterbalancer shaft forward and when the gears lost mesh the timing was lost.....and then a mighty wack knocked the front of the engine out and onto the pavement!

I believe this photo shows the point at which the crankshaft counterweight began to contact the counterbalancer....the mark on the rod likely occurred once the gears separated and the timing was lost.
https://imgur.com/vgNFuh4

I believe the damage to the counterbalancer pin likely occurred as the crankshaft hit the counterbalancer - I don't believe it was the cause of the failure.

Why the flange broke on the crankshaft sprocket.....I don't know. Perhaps it was not torqued properly. Perhaps it was damaged when the shop tried to remove it (Isn't the nut a left hand thread? Perhaps they shop got it overly tightened by trying to remove the nut the wrong way). It could be the shop caused this failure - I have no idea how you can prove it to them at this point.

NOTE: Don't pay any attention to one side of the crankshaft looking discolored while the other half is not - they are all that way. Evidently some heat treating process at the factory causes that - several of us have been fooled the first time we see that funny color on half the crank.

Title: Re: s40 major failure, balancer hitting case, caus
Post by stewmills on 06/29/20 at 11:28:31

I haven't read this post in detail to really know what's broken and what isn't, but I have a 95 engine that I got as a parts engine after the top end was messed up due to a cam chain tensioner failure. If any of the 95 parts are compatible with yours (don't ask me...I have no clue) and would get you back on the road you can have what you need for the cost of shipping to SD.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/29/20 at 11:35:59

OK, I give up. :o

Dave, how did you get this picture???

"The flange broke off the back of the sprocket that goes on the crankshaft and holds the primary gear.
https://imgur.com/SXPtib"

Very interesting indeed. So do we have a situation where the cam drive sprocket failed in a way that the flange broke off but the sprocket portion remained engaged....or.....did the entire sprocket fail? Does Blake have a bunch of bent valves?

If the cam drive sprocket is the root cause (which seems plausible), how did the balancer drive gear pin end up falling out?

I think it may have been a failure that was a long time in the making. For instance, the flange fails on the cam drive sprocket, which relaxes the pinch on the balancer drive sprocket, which allows the balancer drive sprocket to start moving, which starts working on the pin, and the pin eventually gets worked loose from the constant pounding back & forth. That round pin falling out plays a major role here.

How in the world did you get that picture of the fractured cam drive sprocket?????

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/29/20 at 11:45:48

@Dave

I didn't notice any freeplay side to side on the crankshaft, at least it wasn't enough to be noticable. I even tapped it on both sides with a dead blow hammer to check for movement after this was brought up previously.

@stewmills

That was the first thing I checked and what I assumed was the problem before I started disassembly. The chain tensioner was completely fine as was the cam chain.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/29/20 at 11:49:40

@DragBikeMike

Valves are fine and made no contact with the piston. I turned the engine before disassembly and it felt like it made good compression. Everything in the top end looked great as far as I could see.

Title: Re: s40 major failure, balancer hitting case, caus
Post by stewmills on 06/29/20 at 12:32:25

@BlakeEM, I knew you had already looked at the CCT stuff, I was mainly offering free parts (not technical advice) if I have anything you can use from a 95 that has a bad top-end. Got this motor free for parts, so just paying it forward if you can use anything for the cost of shipping. It has been partially disassembled by the previous owner, but if you can tell me anything you need I'm happy to dig around and see if it is there. I just don't know what off of a 95 you would, would not want to put on your year model...I don't know enough about the differences to answer that question for you.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/29/20 at 12:57:54

@stewmills

We are just going to part it out. She really needs a more modern bike with fuel injection since it's a daily. It lasted her a good 5 years. Thanks though!

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 06/29/20 at 13:24:13

Well,, where are ya and what do ya want for the fork tubes?

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 06/29/20 at 13:52:19

DragBikeMike: The photo of the broken flange came from a previous post. The sprocket is splined all the way through, so when the flange broke off the cam would still be in time.....the loss of the flange does not allow the sprocket to spin on the crank and change the timing.

I do agree that you are likely correct in thinking the crankshaft gear and pin for the counterbalancer likely started moving around once it lost the clamping force when the sprocket flange broke. It very well could be the pin broke and the counterbalancer shaft went out of timing and that is what happened when the engine blew the counterbalancer out the front of the engine.

BlakeEM: The crankshaft is a snug fit in the ball bearing - so you won't be able to pull on the end of the crank and get it to move in the bearing and feel any side to side play in the crank. The movement of the crank to the right side may have taken a while to occur......and that is likely why the failure didn't occur immediately.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/29/20 at 18:17:09

657A7C7B6661506050687A763D0F0 wrote:

Well,, where are ya and what do ya want for the fork tubes?

If anyone is interested in any of the parts you can get more details and ask about them here. I don't want to clutter up this thread.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1593479677/0

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/29/20 at 18:36:04

Whoah! :o

Dave, is that busted sprocket picture from a previous post by Blake....or.....some other member's busted sprocket?

Blake, is that picture of the busted sprocket from your engine....or.....is all this stuff about the busted sprocket purely speculation? Is your cam chain drive sprocket all in one piece or is it all busted up?

I appreciate your help on this as I have to make a decision based on your answers. Please clarify.

Also, note that Blake submitted a picture of his right hand main bearing. It looks like it drifted to the left about 1/8" or so. If that bearing controls the axial position of the crankshaft, what restrains the bearing outer race? How do you control the axial position of the crank (right/left) if the main bearing isn't somehow locked in place?

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/29/20 at 18:39:03

Are you talking about this? That is what I found when I removed it.

https://imgur.com/SXPtibU

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 06/29/20 at 18:55:58

Yes. That's what I'm curious about. Somehow, that picture didn't show up in the string of posts that I could see. So, that totally failed cam drive sprocket is all yours.

Thanks very much. I have no clue why that particular post wasn't in the string that I was looking at, but it clears up a whole bunch of stuff.

What a mess. Really a spectacular failure. Your wife is so fortunate. Good luck with the fuel injected replacement and muchos mahalos for sharing all the great photos.

Best regards, Mike

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 06/29/20 at 19:01:09

Tale a close look at the nut on the end of the crankshaft - it sure looks to me like somebody hammered a while on this nut in the counterclockwise direction with an impact gun.
https://imgur.com/CCwkG9c

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/29/20 at 19:26:00

63585542535F444259515C43300 wrote:

I noticed that as well...

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 06/29/20 at 20:02:47

Look at the case behind the gear.
It's been shaved by the teeth.

And yeah,, someone got down, rattling on that nut. If that's tightening, AND it's a place where over tightening is bad , somebody's got some explaining to do..
You might hold off on selling me those forks,, dangitt,,I need some forks..

Title: Re: s40 major failure, balancer hitting case, caus
Post by Hiko on 06/29/20 at 20:40:15

That looks to me where the problem started.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Ruttly on 06/29/20 at 22:29:58

You cannot use a impact to install that nut , ok to take it off , thats a hand tighten then torque it nut. Or your gonna have a problem. Guess I was lucky when I heard it break ( cam chain drive gear/sprocket ) . So that’s how I know. And everyone who has used a impact gun on it had better go back in and check it. I’ll have that cover off soon to change the clutch pushrod to the proper length and i will recheck it. That’s the last thing I need to happen while breaking the ton mark !!!

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 06/30/20 at 02:31:10

I think it's more likely he used an impact wrench to remove it not realizing it's reverse thread at first since it was his first time working on this specific engine (he usually works on high performance track bikes). He's a master mechanic so I assume he torqued it properly when it was installed however the damage would have already been done. It's hard to prove anything and I don't know what I'd expect the shop to do about it. It's a very crappy situation and the shop is extremely unlikely to admit the mistake however the shop owner is asking the tech about it.

I don't see any other way to make sense of it, those marks and the scrapes behind the drive gear seem like the smoking gun.

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 06/30/20 at 08:23:20

I think its obvious enuff.. That nut Says
Impact, CCW..
Which results in Overtorque,,and damage done..
Once he realized the mistake, flipped the switch, CW impact, took it apart..

Too late,, damage done..
Thats the only thing that adds up in my mind

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/01/20 at 11:09:32

I'm riding over to talk with the tech today. Wanted to get some pictures to prove that the crankshaft was out of alignment as well as a picture of the hole for the main drive pin on the crankshaft.

The hole for the pin in the crankshaft

https://imgur.com/8EzRg9g

I noticed the main bearing wasn't fully seated, you can see the gap.

https://imgur.com/f0wmwca

https://imgur.com/DBp00WV

On the other side it looks like the crankshaft was scraping the case. Notice the white part.

https://imgur.com/npU7tD9

I don't have a flywheel puller. Is there an easy way to get off the flywheel so I can get a better look or do I need a puller?

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/01/20 at 12:39:19

From what I've read I need a puller, so I probably won't be getting it off anytime soon. I wanted to have a look at those bearings.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/01/20 at 12:54:45

You don't need a puller for the flywheel - you need the puller for the magnetic rotor.

You do need a big deep socket to get the flywheel nut off though - and if you don't have an impact you will need a holder for the flywheel to keep it from turning while you loosen the nut.

The rotor is on a tapered shaft, and there is no way to get it off without a puller. Take it to the shop with you and maybe they will pull it.

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 07/01/20 at 13:04:59

You mite wanna do your arguing with the mechanic before ya go deeper,,

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/01/20 at 16:18:24

I believe I know what happened after talking with their tech.

This could not have happened from over torquing the main drive nut. The marks on the nut were from his impact on the low setting (45 ft-lbs) and he torqued it by hand. Over torquing this bolt would put pressure on the bearing and it's not possible for it to move the crankshaft since it pinches the side of the case.

What we think happened was that the key in the balancer sheered off over time. This bike saw a LOT of freeway. At high speed the balancer was making contact with the crankshaft. The crankshaft has a small amount of play side to side from the factory, this is that gap we see in the bearing seat. The crank likely saw a lot of vibrations and this caused the main drive pin to come loose causing the balancer to spin freely and leave the engine.

So I think the weakness is that balancer key, this can cause your balancer to loose timing and hit the crankshaft. Over time this can cause the crank to shift side to side and the main drive pin to come loose.

It blew when coming off the freeway. Before that it made a sound similar to a misfire or exhaust leak, this was likely the balancer hitting the crankshaft.

See the failing balancer key here.

https://i.imgur.com/VEBUgRo.jpg
https://i.imgur.com/F7ldFCB.jpg

If you use this bike for a lot of freeway riding this could be a major failure point to watch out for. The balancer has springs to dampen the rotational force so although it has a 1/2 inch gap when not moving when running at a high speed this gap will shrink and if the pin starts sheering off it gets even smaller and it can hit the crankshaft.

Hopefully this makes sense and provides some closure.

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 07/01/20 at 16:21:11

He didnt do That with an impact,,

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 07/01/20 at 21:00:53

Now do you want to sell the forks?
Mine broke when a woman turned left across me..
I could use the tank, too.
Mine got bent,,

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 07/01/20 at 21:02:16

Need some other stuff, but need to look again,, left peg is off, but don't remember exactly what got smashed.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/02/20 at 04:37:18

BlakeEM:

The bike is not damaged by freeway riding......we have lots of riders who do that every day. Our member Oldfeller was the king of high rpm riding, MMRanch has been to Texas and back to Tennessee several times, and I believe Batman is a daily highway rider. Your bike is the only one on this forum that has ever done this. The only known issue with extended freeway riding at high rpm is the oil consumption increases, and you need to check the oil level regularly as it will drop faster than normal.

The "TECH" caused this damage with the impact wrench when he was taking the bike apart......not when he was putting it back together. He mistakenly tried to remove the "left hand thread" nut by running it counterclockwise in the right hand thread direction - that is when the damage was done. The over-tightening while trying to loosen the nut in the wrong direction resulted in the camshaft drive sprocket flange being fractured........and no matter how careful the tech was when he reinstalled it - the stress cracks were formed and over time the sprocket flange broke off and allowed the clamping tension to be released. Once the clamping tension was released everything on the right side of the crankshaft was no longer properly attached and things began to move around in a destructive way. The damage to the key and pin and ultimate engine destruction were all caused by the parts no longer being clamped together and the resulting "hard impact" when the crankshaft hit the balancer shaft.

The Suzuki Savage is fully capable of freeway riding when properly assembled - the "tech" at the shop is at fault for this engine failure.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/02/20 at 07:32:15

@Dave

Could you explain how the release of clamping force would cause the balancer to hit the crankshaft? Because this was happening a while BEFORE the pin came out of the main drive gear. The crankshaft is free floating side to side so the loss of clamping force would not have caused that to happen nor would it have caused it to jump teeth on the gear since it's made to move side to side (there is no evidence of it jumping teeth). The only cause that makes sense is that balancer key failing first, especially based on how it failed. We thought the sound was an intermittent misfire or exhaust leak but it was only on the freeway at full throttle. I tried resealing the exhaust a couple times and she was complaining about issues at high speed for a while as well, I just couldn't pin point it. It may have been hitting it for a while. Most of my test rides were around town however it was only noticable at full throttle on the freeway.

Just because it hasn't been mentioned on the forum doesn't mean it can't happen. Others have mentioned that key being a weak point.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/02/20 at 07:41:59

I shouldn't have said clamping force before since it doesn't actually clamp that side of the crankcase, it clamps between the nut and the crankshaft which freely floats in the bearings.

The guy is a master mechanic and I'm just a hobbyist. He drew it up on paper to explain it to me and it made sense what he was saying.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/02/20 at 07:45:16

When the clamping force was lost, the crankshaft was no longer prevented from moving within the right crank bearing.......this right bearing is a ball bearing and is what keeps the crankshaft centered (the right bearing is a roller bearing and accounts for the different expansion rates as the engine warms/cools.

When the flange on the sprocket broke the crankshaft moved left (as evidenced by the gear cutting into the right case half). When the clamping force was lost as the crankshaft moved left, the gear on the crankshaft that drives the counterbalancer was no longer contained and it was able to start rocking forward/back as the power and compression pulses occurred - and over time the pin was distorted and came loose toward the inside of the crankshaft (you showed a photo of that pin extended to the inside of the crankshaft). Once that pin was no longer keeping the counterbalance shaft in time with the crankshaft.....the timing between the two was lost and the destruction began. The pin does the locating and provides some of the strength needed to keep the gear in time with the shaft - but the clamping force also prevents movement.

The gear on the counterbalancer shaft is dampened with springs to help smooth out the rotation at varying frequencies and reduce the load on the key that was damaged - I suspect the damage to the key actually occurred when the collision between the crank and counterbalancer occurred.

I have been on this forum for more than 8 years, and I have seen a lot of stuff........this is the first time anyone has had this type of failure. You and your riding style did not break the engine.......your mechanical "tech" did.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/02/20 at 08:02:33

Torque on that nut puts zero pressure on the crankshaft so it's physically impossible for that to be the case.

Again, the clamping force is between the end of the crank and the nut so no amount of torque could have caused this. Even if it was 500 ft-lbs the crankshaft would have the same amount of free play regardless. It's more likely that's caused by the excessive side to side free play in the crankshaft that exists from the factory. He said they old R1s had similar issues when they had too much side to side free play. This was the only time he ever seen marks like that. I trust the guy, he made me feel like an idiot talking to him. He builds race engines daily.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/02/20 at 08:05:20

That nut was still tight when I removed it, I had to use an impact to get it off. If it "lost clamping force" it would have been loose. The flange damage was from the crankshaft banging side to side most likely. This can explain the damage to the case as well.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/02/20 at 08:14:58

The fact that the bearing was out of it's seat makes sense based on what he said and this is what caused the scapes under the main drive gear/case and the broken flange. As the crank went to the side it hammered the bearings moving them out of the seat and hitting the case on both sides.

Title: Re: s40 major failure, balancer hitting case, caus
Post by justin_o_guy2 on 07/02/20 at 08:28:52

Then do you want to start selling parts?

Because Im gonna have the money in a week,,

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/02/20 at 08:33:59

@justin_o_guy2 post everything you want here. No one has claimed the forks yet. I should be able to start disassembling it today and I'll post pictures of individual parts. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1593479677

I want to keep this thread specific to discussion about the engine failure.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/02/20 at 08:40:23

This photo shows the flange was completely broken off:

https://imgur.com/SXPtibU

The diameter of the low point in the cam drive sprocket is 1.105" (The caliper shows 1.120 as it moved when I set it down to photo).

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/02/20 at 08:41:23

The diameter of the crankshaft where the right ball bearing slides over is 1.378":

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/02/20 at 08:42:48

The result is that the crankshaft is more than 1/4" larger than the low point in the cam sprocket:

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/02/20 at 08:47:34

So when the "Tech" broke the flange off the sprocket.....the remaining inner portion of the cam sprocket was able to move inward and it tightened up against the crank (rather than the flange tightening up against the inner bearing race) - the flange that is supposed to clamp on the bearing was cracked or broken and was no longer able to push against the inner bearing race.

With the flange being broken off and no longer pushing on the inner bearing race - the clamping force was not being transferred through the bearing race and holding tightly onto the counterbalancer drive gear.

Title: Re: s40 major failure, balancer hitting case, caus
Post by BlakeEM on 07/02/20 at 09:05:07

That flange wasn't broken off, it was perfectly in place when I removed it, I just didn't get a picture. It was likely damaged from the side to side motion that pushed the bearing out of the seat.

Title: Re: s40 major failure, balancer hitting case, caus
Post by Dave on 07/02/20 at 09:09:48

Okey-Dokey

Hope you have better luck with your next bike.......and mechanic.

Title: Re: s40 major failure, balancer hitting case, caus
Post by DragBikeMike on 07/03/20 at 01:42:24

"That flange wasn't broken off, it was perfectly in place when I removed it"

I hate to tell ya this Blake, but that flange was broken off (like completely broken off). Just because the remnants were captured in the fracture doesn't change the fact that it was broken.

I am a bit surprised that centrifugal force didn't throw the chunks out of there, but if you assess the entire design you can see why. There's a bellville washer in between the nut and primary drive sprocket. That concave washer continues to apply force even if the sprocket migrates to the left. That force from the washer kept the chunks of sprocket flange clamped between the nut/washer and the end of the crank. Unfortunately, there was no longer any force being applied to the bearing inner race, or the balancer drive gear.

Dave's evaluation makes perfect sense, and the photos he provided give almost a perfect visual description of the problem.

This design is a land mine. Yes, it is probably a very rare failure, but it has the potential to kill someone. As I see it, there are a number of design problems, and when the planets are in alignment they can all come together to be disastrous.

First, the nut is LH thread. Yes, it has to be LH thread but the designer should be taking into consideration that more than likely someone will screw up and try to turn it the wrong way. That almost always occurs on disassembly and the offending mechanic more than likely will really reef on that bad-boy trying to get the thing loose. Then there's the potential for rattle-wrench application. Ruttly has been harping about this sprocket for a long time. We should all pay attention. Thanks Ruttly, you definitely have my attention now. I think cracking that sprocket set the groundwork for your BIG failure. Whoever designed this should be thinking about maintenance too. If you must use a LH nut, design the system so the internal threads on the cheap nut will fail before more important stuff (like the sprocket), or make the more important stuff more robust so they can handle the over-torque.

Second, the flange on the sprocket is thin. You can see that the designer did a good job on the filet on the flange (it's generous), but the flange bears on the bearing inner race at a point that looks to be beyond, or right at the edge of, the fillet. Now when you tighten the nut it causes the sprocket flange to bear hard on the inner race at a point beyond the edge of the filet. It applies a bending moment on the flange and a BIG stress concentration right at the edge of the fillet. I guess that's fine as long as you don't overtighten the nut.

Third, the designer is relying solely on friction between the balancer drive gear, the bearing inner race, and the crankshaft. I know there is a drive pin, but the pin is not an interference fit. It has a little clearance so that you can assemble and disassemble the gear from the crank. I guess that's fine as long as the nut doesn't come loose. But guess what, stuff comes loose sometimes. Ya gotta be thinkin bout that stuff.

Fourth, the drive pin (the round one) is not captured. That hole in the crank should be stepped so that in the event that the drive pin starts to creep it can't come all the way out and let all hell break loose. Your pin clearly came out, and that was the nail in the coffin.

All of that mumbo-jumbo about the crank moving right and left and bustin up the sprocket. Malarkey.

I previously said we shouldn't be so quick to judge the mechanic. Now that all the other bits of info are on display (I'm lovin the pics, thanks again), I don't know who's more at fault, the person who designed it, or the person who worked on it last. :-/

Title: Re: s40 major failure, balancer hitting case, caus
Post by Ruttly on 07/03/20 at 12:46:49

Add a post it note to that page in your manual
Reverse/left hand threads,use no impact here,tighten & torque by hand

I hate making the same mistake , again !