shattered piston= high idle?

[cr87]

my friend is now having the same problem i had a while ago. the previous owner sold him the bike telling him he used starter fluid on it and now the idle is very high. well when we took the top end apart we noticed the piston has cracks in it and some pieces are also broken off. is this the cause of the high idle?

[1987CR250R]

No, probably not. The cracks are a result of high hours or excessively loose clearances. The high idle is probably unrelated. Put it back together (with a fresh piston of course) , fire it up, then start tweaking the carb to try to bring the idle down. If it won't come down, suspect air leaks.

[BlazeNtrigger]

my friend is now having the same problem i had a while ago. the previous owner sold him the bike telling him he used starter fluid on it and now the idle is very high. well when we took the top end apart we noticed the piston has cracks in it and some pieces are also broken off. is this the cause of the high idle?

Lol , no im sure you got a air leak. The cracks and pieces missing are normal and happen all the time.. I dont think half a piston missing will cause your idle speed to be high. *

* Sarcasm - I would fix the big issue like having 1/2 a piston in your bottom end. I wouldnt even START the bike if I where you never mind try sort out the idle. Get a new piston kit , inspect the cylinder , split the cases and make sure you get ALL the metal pieces out BEFORE you put in the new topend and start the bike.

[DFlan]

There isn't much room between the crank and crankcase and a piece of piston could have cracked the case causing an air leak.

[cr87]

could it also have been my gasket? ive heard of people having head gaskets go bad causing a high idle too?

[1987CR250R]

Burned a head gasket out on my bike, it simply wouldn't start.

[Big_G_Hall]

Dang man I think you got bigger problems than a blown gasket...