Continental made a DECO engine that was used on quarter midgets and all sorts of hop up parts were made for those. I think there were some AU7 and AU8 Continentals that drove those karts as well, but the AA7 was a stationary engine without the performance. The Solt company made go-fast parts for the engines above, but I don't know that they fit AA7, only that all of that stuff is expensive. Still, those are neat little engines, and on the right bike could be pretty cool. Just don't plan to go real fast.