Motor ate Valve shim.. **RESOLVED & PAID**

[The_Paragon]

Yepp.. thats what happened. 

Essentially a valve shim ended up between the chain and the cam chain gear on the crank. Broke the cam chain, and chipped a tooth on the crank gear. Meanwhile the cam lobe spun inside of an empty bucket and chewed up the cam lobe and top of the bucket. Also the valves are bent.
Chunks of broken valve shim are everywhere.

So what gives? Valve check and shim were done at 11,600 miles (about 2000 miles ago).

My thought is that the valve shim simply broke apart (they were either Hot Cams or K&L, I'll have to look back).
Or a bucket may have stuck, Though it seems that the bucket still spins free in the head and can be compressed ok.

Any thoughts on this forum?

(I'll throw some pics up when I get a chance.)

[HPP8140]

extra large clearance? over rev for long period of time?

[ace50]

What were the circumstances when this happened? 

[The Buddha]

Gorilla mechanic
I've never head of a GS spit a valve shim out.
Old school GSXR's 91-92 1100 and 89-90 750's I believe used to, but those shims were tiny. Not the 1/2 dollar sized on the GS.
Cool.
Buddha.

[gsJack]

Was the shim that failed an OEM or an aftermarket one?  What was the gap after the last valve check 2k miles ago?  What was the max engine rpm just prior to the big bang?

I started setting exhaust valves at a wider .003-.005" (.08-.13mm) clearance about 9 years and 70k miles ago on my 02 without a problem and with much greater exhaust valve life.  Use to run my 97 for hours on end at 7-9k rpm in the mountains without a problem but was never much for redlining a stock GS engine.

Offhand I tend to agree with your shim failure theory.  Very rare to hear of a thrown shim on a GS engine although it's happened in rare cases.

 

[The_Paragon]

I took off from a stop sign. Got into the throttle a little bit.. revved up to about 8000 rpm then shifted. As soon as I grabbed 2nd gear, I got about 10 loud knocks, and it was all over with.  The Knocks were the pistons making out with the exhaust valves. <That right there is about as hard as this thing is ever driven. Its my GF's bike and she never spanks on it.

Sorry Budda, no gorilla mechanic here. I did the valve shim job and set them within specification.

[The_Paragon]

One more question. It looks like I can get a 2001 head from a forum member. Are there any major differences between an '06 head and an '01 head? That a swap wouldnt work? I already have the Pair ports blocked off, so its not an issue to me if the '01 head doesnt have pair ports.

[The_Paragon]

Was the shim that failed an OEM or an aftermarket one?  What was the gap after the last valve check 2k miles ago?  What was the max engine rpm just prior to the big bang?

The failed shim was an aftermarket. I'll have to look back in my log book, but the last I think I ended up with .003 on both exh vavles when I did the check.

[The Buddha]

Was the shim that failed an OEM or an aftermarket one?  What was the gap after the last valve check 2k miles ago?  What was the max engine rpm just prior to the big bang?

The failed shim was an aftermarket. I'll have to look back in my log book, but the last I think I ended up with .003 on both exh vavles when I did the check.

Oh crap ... I've got all sorts of shims in the bikes I did em on ... did it break when it was still in the bucket ?

Cool.
Buddha.

[The Buddha]

BTW you need a whole motor IMHO. Crank with a broekn cam chain tooth wont work.
Cool.
Buddha.

[The_Paragon]

It must have broken inside the bucket. not sure how else it would get out of there unless the bucket was stuck and stuck the valve open.

As for running the gear with a broken tooth.. it might be ok..

I really dont feel like dealing with buying a whole motor.. Does it pay to spend $800 for a motor on one of these things? I havent been able to find but one newer motor on ebay for $800. Might as well give the cheap repair a shot and see what happens.

[gsJack]

From all you say it doesn't look like a shim was thrown with the exhaust valves set at the .003" factory spec max and it's highly unlikely a bucket stuck on a warm engine.  I had a tight exhaust bucket on my 02 when it was cold and and it was tight enough that the valve wouldn't close all the way.  No compression cold but good compression warm on that cyl.  The engine would start up running rough and then smooth out within a minute as the aluminum head heated and expanded to free the tight bucket.  I decided to let it go to see if it would wear in since it presented no running problems for the rest of the day after the first minute.  But one freezing cold morning the even tighter bucket held the valve wide open and bang, a broken exhaust valve but little other damage since it happened while at cranking speed.

Any chance you had a cam chain tensioner fail at 8k rpm that caused a cam timing change allowing the valves and pistons to clash resulting in a bent valve to be held open allowing the shim to escape?  Give the tensioner and chain a good look over.  A chipped cam tooth on the crank I guess might still work depending on how much it's chipped.  Sounds like something I might try myself but wouldn't advise someone else to do.       

[The_Paragon]

From all you say it doesn't look like a shim was thrown with the exhaust valves set at the .003" factory spec max and it's highly unlikely a bucket stuck on a warm engine.  I had a tight exhaust bucket on my 02 when it was cold and and it was tight enough that the valve wouldn't close all the way.  No compression cold but good compression warm on that cyl.  The engine would start up running rough and then smooth out within a minute as the aluminum head heated and expanded to free the tight bucket.  I decided to let it go to see if it would wear in since it presented no running problems for the rest of the day after the first minute.  But one freezing cold morning the even tighter bucket held the valve wide open and bang, a broken exhaust valve but little other damage since it happened while at cranking speed.

Any chance you had a cam chain tensioner fail at 8k rpm that caused a cam timing change allowing the valves and pistons to clash resulting in a bent valve to be held open allowing the shim to escape?  Give the tensioner and chain a good look over.  A chipped cam tooth on the crank I guess might still work depending on how much it's chipped.  Sounds like something I might try myself but wouldn't advise someone else to do.     

I was wondering about the idea of a stuck bucket, but it didn't present any of those symptoms. and seeing as the bucket still rotates and I guess I would rule out the idea of a stuck bucket.

As for the cam tensioner, Its fully extended as it sits right now. It doesn't look broken or defective by any means.

The cam chain looks terrible. Broken in two spots and links are twisted where the breaks are, like a piece of steel got caught between it and the gear it was wrapped around.

[The Buddha]

Oh, did you ruin the rear cam chain guide ? If so, you're gonna have to split the cases. Get a motor, dont even bother with this one. The rear guide should look pristine. Else forget it.
Cool.
Buddha.

[The_Paragon]

Oh, did you ruin the rear cam chain guide ? If so, you're gonna have to split the cases. Get a motor, dont even bother with this one. The rear guide should look pristine. Else forget it.
Cool.
Buddha.

Ha, Thanks.. That was my next question. How do i get the lower cam guide out because that thing is chewed up.. Splitting the case doesnt sound appetizing. It sounds like I might have to go with your suggestion here and ditch this motor. Its just turning into a can of worms.

I was able to locate a used motor with ~2000 miles on from an 07 somewhat locally for $750, I might just have to pony that up and buy it to get this thing back on the road.

[prmas]

I tend to agree with GSJACK. I think that the "spat" shim is the result of chain or guide failure resulting in piston/valve contact, not the cause of the failure. It is EXTREMELY unlikely that a shim could eject itself at less than "valve bounce" revs. If the engine had run normally for 2000 miles it seems that the shims were fitted correctly. I am currently running .003" inlets and .005" exhausts with the only noticeable difference a quietly audible valve/tappet noise between 3000 and 4000 rpm. At all other revs it sounds the same and performance is the same. 

Macka

[HPP8140]

I also had a rear guide failure, but much less damaging because the engine was not running. I heard a noise one morning at startup.

http://gstwins.com/gsboard/index.php?topic=67355.0

[The_Paragon]

Well it looks like Ive located a motor. Just going to go that route and stick a used engine in it..

I hate to admit this.. but this thing is probably going to hit the road after this.. makes me sick looking a 13,000 mile suzuki exploded all over my garage. 

[The_Paragon]

Well, new engine is installed!
The GSer lives again!

[AlexT]

Just saying, I've threatened to sell my bike each time my GS has left me on the side of the road. Then I end up fixing it, riding it, and forget all about the silly thought of selling