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Yz250f adding extra barrel length

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my bike recently blew up, the piston clip came out and scratched up the whole bore. so I brought a new one from a wrecker, I brought all new piston and rings and put it all back together. an hour of riding the bike shits itself. I tear it apart and find the piston hit the top of the head and it broke the aluminum mold for the pin on Conrod, I felt pretty lucky since I only have to replace the piston. I Measure the difference in bore length and it's only half a mm. what should I do to make the bore longer, and another base gasket? buy a larger gasket?

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If the piston hit the cylinder head, you should first check for a bend connecting rod.


After you first failure, was the broken circlip located?

If not, that may come back and haunt you if/when it dislodges itself from it's hiding place.


Partial rebuilds after a failure are rarely successful, 

if you'd rather spend more time riding than wrenching

you'll have to me more thorough in inspecting the whole engine

and not just replacing a few parts in the hopes it will be 'fixed'.


Edited by mlatour
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