Figured out why it had a miss

[Yamaharider74]

Well just recently put my engine back together ran sweet has stage 1 mpi supercharger with a gems controller but then it starting reving up and down all on it's own , figured out what that was air sensor out of air box zip tie broke and it fell in backside of clutch , so then took it out again give her a little but ran great again then pin it again let off then it starts missing so put on trailer take to shop pull throttle bodies off then I see 3 of the intake valves are bent and banged into the head so take apart only to find piston banged up from valves exhaust and intake valves all no good on that cylinder

 

[Yamaharider74]

Well just recently put my engine back together ran sweet has stage 1 mpi supercharger with a gems controller but then it starting reving up and down all on it's own , figured out what that was air sensor out of air box zip tie broke and it fell in backside of clutch , so then took it out again give her a little but ran great again then pin it again let off then it starts missing so put on trailer take to shop pull throttle bodies off then I see 3 of the intake valves are bent and banged into the head so take apart only to find piston banged up from valves exhaust and intake valves all no good on that cylinder

would ice or water cause a valve to break off causing all this

 

[mbarryracing]

Just that one cylinder? Check that this piston is moving up and down properly, ususally if it was cam timing then all the valves would be no good, and if it was a backfire that caused the valves to hang open to get hit, it's usually the exhaust valves that get dinged...

 

[Yamaharider74]

Just that one cylinder? Check that this piston is moving up and down properly, ususally if it was cam timing then all the valves would be no good, and if it was a backfire that caused the valves to hang open to get hit, it's usually the exhaust valves that get dinged...

okay that would make sense it did backfire slightly when I let off just before it started running rough ,god dam it that's likely what happened then the exhaust valve hung open broke off and knocked all the other valves out on that cylinder all the other ones had a nice burning color to them