I just bought a WR400, and I don't think the motor has ever been touched (as far as I know). I was planning on getting a new piston for it this winter, and possibly get a new cam chain. Im not planning on doing anything with the valves, unless I see a problem when I do the piston. I would like to know what other things I should do/replace for peace of mind? Ive read about how the 426 rod end was 2mm bigger and it is possible to switch my crank out for it, but what parts would I need for such a conversion?