I am in the market for a used yz450f and was wondering if people had any issues with the 4 speed tranny gear spacing. I plan on doing a little MX track use but more riding in the woods (mixture of tight and fast trails) and some dune riding with a paddle tire. Would the 4 speed tranny have to large of gear spacing for tight woods use or run out of steam on the top end? Would I need to have a bunch of sprokets depending on what i wanted to use it for? (wide open on dunes and some dune hill climbs) I would be looking at 450's btw, not 426's.