Ok, I do know over reving will kill a fourstroke. My Dad has a CRF450R, its a 4-stroke race bike and that engine will turn 12,000-13,000rpms and reading on it, I always heard DON'T OVER REV" so I do know about the valves flowting (sorry if my spelling is of or bad, I don profread any thing on here.)

and as far as cooling, I plan on make a fan that will run off the engine's rpm's, kinda like a supercharger would, gearing I know I'm going to have to gear that thing aLOT.

I'll I need to know is stuff like tuning, maintence, how many gallons, (just a ruff amount) what temp the engine should be ran at, ringed or ringless, do I have to check the valves, or shim them (like my Dad's bike) and when I rebuild a 4-stroke engine, do I have to replace the piston, sleeve, piston ring (if there is any) and con-rod?