I did a ground up refresh of my '01 CR500R engine in a '02 CRF450R frame. Yeah, it's an MPS conversion and I know all of the complaints about the welds, head-stays, and anything else a person can complain about; but, mine has held up fine for over 6 years with no problems. Only thing left is to pull a couple of dents out of the pipe. Redesigned the airbox using Eyesky's info.
but mine has held up fine for over 6 years with no problems
they only break if you ride them
the 450 will have less power and will be harder to start, and will be heavier, but to make up for it it will require more maintenance.
4stroke=dead fish
