I dream of using an XR200 or XR250 dirt bike engine on a bicycle. You think that a predator 212 is powerful?
A 1980's OHC XR200 will rev to 9000+ rpm and will produce 19hp in its stock configuration with 200cc of displacement, according to the manual! O.o Probably closer to 13hp in reality tho. It also includes a real motorcycle transmission.
The XR80 engine I'm using on my board track build produces around 5hp stock. I hope that EFI, free-flowing intake and exhaust get me to 7hp. All on 80cc.
I should be able to break 10,000 rpm.
I can't wait to get this build done and post a video.