HELP

[yamaha man]

Ok so this is really odd. My piston blew up on the right side but the crank bearing went out on the left side?? Normally wouldnt it happen on one side? Also what might of caused it, because the jetting was perfect.

[mopar1rules]

shit justs happens i guess. did the piston skirt break off? if so, that would be from too much piston/cylinder clearance.

[sheefreak]

Jetting usually will not have anything to do w/a bearing failure. As mentioned, sometimes a crank bearing fails because you are unlucky. The obvious causes would be a ton of time on the crank, and no mix oil in your fuel. Usually when a crank bearing goes, pieces will get pushed up through the transfers and destroy the top of the piston on that side, but the two sides are not sealed off. It is possible parts and fragments got into the other side. How much time on the crank. And when you say the piston failed, what happened to it?

[yamaha man]

Ran that crank for 2 years and what I meant by piston failure was that half of the bottom part of the piston is gone.. and when i pulled the pipes out of the right side a bunch of metal particles started to fall off.

[yamaha man]

And I think the metal particles are from the piston.

[sheefreak]

Ran that crank for 2 years and what I meant by piston failure was that half of the bottom part of the piston is gone.. and when i pulled the pipes out of the right side a bunch of metal particles started to fall off.

 

It is very possible that the piston failure caused the bearing failure on the left side. Would have also caused it on the right side if it were able to run much longer. As mentioned above, the skirt breaking off is usually the cause of excessive piston to wall clearence. What was your compression like? Was it a hard starter?

[yamaha man]

Nope started fairly easy. I ran with that setup for about 5 months.