First post so hope I get it right.
Lost bottom end on son's 04 yz250f last weekend. Crank and case gone. Head was fine. Since have bought another engine and have ended up with a spare 04 head. I already have a 02 engine with a bad head & cylinder but bottom end is good. Has anyone put a 04 head on 02 engine with any sucess? I know about the auto decompression but all the yamaha part numbers are different on cases, head,cylinder ect. Parts are so expensive I hate to start bolting stuff together and hope it works. I would like to have this 02 motor for a spare. Thanks for any help.