seized piston

tried crowbars, hammering and endless pounding. Its seriously in there. top cylinder is off. not the second. Any suggestions people?

Re: seized piston

Spray some liquid wrench in there, and let it sit for a few days. Then start pounding the hell out of it. Chances are the piston and cylinder will be DOA when you're done, but if it is that hard of seize, they're DOA anyway.

Re: seized piston

what DOA means?

Re: seized piston

Jason Luther /

dead on arrival. ambulance jargon

Re: seized piston

what he said or PB blaster

Re: seized piston

Jason Luther /

try heating the cylinder with a propane torch. but please, make sure there isnt any gas anywhere around.

Re: seized piston

How did it fail?

Is it stuck from sitting for a number of years? If so, the rings are probably rusted to the cylinder. A lot of posters recommend tilting the bike up and soaking the cylinder with Kroil or Marvel Mystery Oil then knocking it loose.

If the failure happened while you were riding, the piston has probably welded itself to the bore. This is serious trouble.

If the cylinder can be loosened from the crankcase, try rotating the engine to raise the cylinder and the stuck piston away from the crankcase. If it can be raised up, make some hardwood shims to fit between the cylinder base and the crankcase. Slip in the shims, rotate the engine to seat the cylinder on the shims, then bang the hell out of the piston by placing a hardwood block on the piston and hitting it with a large hammer.

As a last resort, you can get a carbide grinding bit and cut the piston out of the bore. The problem with this is that you will get grindings in the crankcase which means that you will have to take the crankcase apart to clean them out.

Good luck

Re: seized piston

All suggestions so far are good; I'll add another.

If you can see the piston skirt through the exhaust or intake port, put a big punch through the porthole and start hammering. If you are lucky, you might be able to collapse (buckle) the piston skirt, and that should help free it up. This assumes that the piston is seized to the bore, in which case it's already a loss and busting the piston won't hurt things any further.

By your comments about crowbars etc, I take it that you already assume the piston/cyl are a loss.

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