Piston Direction

[dirtmonkey65]

I just finished doing my top end and the engine is running a little rough. How rough would the engine run if the piston was installed backwards? Would it even start?

 

[Robcolo]

Yes it would start --and may not even rough, but you'd be sucking some crap from the exh pipe into the cases thru that piston window. Remove either the carb or the exh pipe and see where the window is --should be on the carb side.

 

[canyncarvr]

I haven't looked, but the piston ring pins will be in a different location. That could be nasty.

Better check it soonest.

There is an arrow on the crown of the piston that should point to the front.