What motor would YOU get ?

i guess if you were trying to keep it 2stroke i would put maybe a lt500r in there or trx250r some thing along them lines..
 
I would go yz400 or yz465 both fast air cooled 2 strokes that need little mods to fit. I personally will be getting a yz400 when I get the money.
 
agreed unstock. too much of a pain with water cooling, and a gsxr 1000 motor? get real. not that it can't be done, but its pointless. sure it can do 185 mph but you would have to make the swinger like a foot longer so it doesn't flip and make it twice as wide so you can turn while actually moving.

not attacking you just discussing.