- Aug 18, 2001
I have heard some talk and done some searches on making a crf450 into a crf500, actually a 498cc but thats close enough. I know that eric has done this to at least a few engines, and I am looking for an update on how this is developing. Are their any reliability issues with this as compared to the 480 big bore? I know that the yz426 can be made to a 444 and a 13.5:1CR piston can be used with good pump fuel (yea, yea, I know all about it Rich...) What kind of CR can be run in this size of engine, are their any head mods that are REQUIRED, and what will the power dilevery be like if the 500BB is acompanied by head porting and an oversize header/big bore specific exhaust system?