So much supply and demand of parts for these bikes parts are very easy to come by for cheap, also an easy bike to wrench on. No need to transplant another engine, plenty of scary upgrades to the engine if you wanted, more comp, porting, bigger carbs, stroked, different cylinders, serval, cub, cheetah, DM etc...plenty of info on this site too, just spend a few hours of reading and you'll be amazed.