Well, honestly, only the 500 engine "fits" the 500 frame. I'd have to say the answer really depends on not only how far you're willing to mod but how far your fabrication skills go as well. I'm currently modding a Zilla frame to accept an XR600 engine. I've always wanted my favorite bike and quad mixed and recently got my hands on a second of both.
I'd go with a mill that has at least the same power or more than original. Anything less and you'll never be satisfied with it's performance. Besides, whats the point of building "down"? Just avoid the 4 cylinder streetbike conversions. I don't care what anyone else says, I've done em. They suck for anything beyond dunes, hillclimbs, and wide cultured trails. Too damned heavy for jumping and tight trail riding. |