I wouldent mess with the rz250...A couple of people on here ( minkia,XTShee ) have put a rz350 motor (street bike motor) in there banshee frame.You can make your shee quick without this motor just get it ported.
Take the engine to someone good and have him go threw the whole engine replacing the stuff thats broken it seems you dident do something right if it keeps on breaking.What oil are you runing?
I think ledofthezep put a 250r swinger on his stock frame.all Blaster,Warrior,Banshee,Raptor,Polaris front hubs are 4/156.Warrior,87-88/91-05 Banshee,Raptor's rear hubs are 4/115. ( 89-90 banshee rear hubs are 4/156 )
that all I could think of.
what the hell are you talking about...i can take a 400ex w/ lid removed by 3-4 bike lenghts in 150y drag...250r's arnt that hot stock....raptors will just get wheelies and i will pass them...ds 650's are fat...450's are nice thou.