Oh poop

[rustybronco]

To make a long story short... I was adjusting the valves last night on my long dormant (nine years) '80 GS850 that I had running last year. I came home from work and started to swap the last two shims around to make the clearances a tad nicer. then, when I started to turn the crank to get the first lobe in position to swap the shims, the engine only turned so far. odd I say... now it only turns 180 degrees.

last night I had turned it at least 20 times around and all was fine and dandy up until this evening without ever a hint of problem.

shims are totally seated, nothing stuck between cam and shim or the bucket. nothing fell in the engine, no kids to drop little bits into it for kicks. who knows for sure what the cause is at this point. so tomorrow I'll borrow a bore scope from work to see what I can, but I think I'm going to have to pull the head.

The bike had 33k miles on it with nothing but 2.75 and 2.80 shims in it. (it now has 2.60's, 2.65's,2.70's and a 2.75 shim)

Oh well, what can you do but grin and bear it.

<end of rant>

[salty_monk]

Bad luck mate. Hope it's something easy... Check the area around the cam chain. You didn't chew a coil lead into the chain or something did ya?

[Dogma]

That is definitely odd. You didn't forget and try to turn it backwards or anything like that, right?

[apogeecustom]

Sounds like the cam chain tensioner is not applying enough force on the chain. Could need some lube.

[chuck hahn]

dont suppose that on a freak deal that one of the buckets is hung up?? wpuld it hurt to take a brass drift and tap on the buckets to see if anything clicks in?? I was here last summer and was watching you..remember?? It was all good then!!! Was while i was getting my carb tutorials..

[rustybronco]

Valve clearances didn't change, no fuel tank on it since last fall, no fuel in carbs, plugs are removed, tensioner works fine, no coil leads in cam chain, nothing at all stuck in it. no damage to the buckets, no turning of the cam with shim removed, ect. I'll pull the stator cover and have a look after 'scoping the cylinders, but it sure sounds and feels like something is touching #3 piston...

no big deal... just needed to vent.

[Steve]

Hopefully you don't find the same thing that I found in #1 son's bike a couple of years ago. Remember my post about the "red pipe special"?

After running the engine at about 4000 to check the stator output, I was interrupted when my son called my attention to this:


Needless to say, we stopped the engine. The next day, I was checking the valve clearances, had no problem rotating the engine to check them all. The next step was shim inventory. I use the zip-tie method to remove the shims, so there is a bit of crank rotation involved. I started with cylinders 1&2, then got the exhaust on #3. While rotating the crank to check the intake, it locked up solid. Backed it up a bit, tried it again, SOLID. Looked down the spark plug hole (larger, because the Timesert had come out with the plug) and saw a small crescent.

Pulled the head to find this:





Here you can see where the valve hit the head.




Ended up getting a replacement head and all is well now.

I shudder to think what might have happened if that valve had let go while the engine was running at 4000, doing the stator check.

As I said, I hope this is not what you find in your engine.

.

[rustybronco]

That is definitely odd. You didn't forget and try to turn it backwards or anything like that, right?

Didn't forget, but had to after it stopped turning the correct way 'round.

hopefully something under one of the engine covers backed out.

[rustybronco]

As I said, I hope this is not what you find in your engine.

.

Gut feeling is I'm going to find something similar...

Bless you chuck for the spare parts engine (a 1980 at that!).

[chef1366]

Do you hear any metal on metal when the motor seizes?
Could be a bad starter clutch or something binding in there.

[rustybronco]

Do you hear any metal on metal when the motor seizes?
Could be a bad starter clutch or something binding in there.

No, but I hear that nice crunch sound carbon makes when it's getting squished.

[chuck hahn]

your very welcome Dale..I didnt really get that good of a look when we were stripping that bike, but how much would you have to do to swap the carbs and such to see if that one i gave you will just fire up?? If you need a weekend spare back let me know...i dont have anything on the plate for this weekend...HINT HINT!!! you can get a lot of mileage out of me for some of the wifes good cookin!!!!

[rustybronco]

your very welcome Dale..I didnt really get that good of a look when we were stripping that bike, but how much would you have to do to swap the carbs and such to see if that one i gave you will just fire up?? If you need a weekend spare back let me know...i dont have anything on the plate for this weekend...HINT HINT!!! you can get a lot of mileage out of me for some of the wifes good cookin!!!!

Thanks Chuck! first I'm going to do some investigating this weekend, then if I need some heavy lifting in a week or so I'll give you a call and see if you are available.

I'm definitely going to fix the engine that's in it though.

[chuck hahn]

you got my number.. and i can bring the truck to pick up the spare for you if necessary...that is if its still in the shed at work.

[thijones]

I'd be more then happy to give you a hand if you need some muscle.