[Warrenmiller11]

i recently put a used engine i bought from a motorcycle scrapyard since the original one suffered catastrophic failure and the bike revs on neutral to 16500 but when i drive the bike stops a 10k and when i touch the headers after 20 min ride two of them are hot and two are cold. i switched injectors spark plugs and coils and still the same two left cylinders dead and the exhaust is glowing red hot overheating?? wild guess i have stock valves from engine sitting on a shelf?? i still have my old head and it looks to be in good condition so im wondering if i should just put my old head on this engine and try it. pistons and rods look undamaged on the used engine. any help be appreciated

 

[Warrenmiller11]

anybody knows if it could be a blown head gasket msybe?

 

[KevA]

I assume you didn't hear the Motor run before you purchased from the Scrappy ?
You need to get a Compression test done to see what sort of Puff pressure she has.

 

[Warrenmiller11]

no it was on a shelf unfortuntly but i dissasembled the head and im replacing with a my head i had from before that i know is in working condition. im puting new gasketd and new piston rings