How about some more info on those.

 

rotary airplane engine is bad ***. Not much ground clearance for that cylinder head, though. I'd have to go with the dual-jet moped.

 

how about a turbo suzuki 4stroke in a YSR?





Optimus_Prime:
luckily, its not hard to fix your problem realisticly...

they put limiters and restrictions in the bikes already.. if it has a speed limiter, you can disable that... most likely it has a large baffle/restrictor in the exhaust.. ditch the muffler and replace it with a open dirtbike one.. (or other compact muffler.)
if you want to start getting into it, replace the tiny carb with a bigger one off of a dirtbike...


oh, and theres always nitrous (no, im not kidding... you can do it easily.. lol)

 

You could also go this route . You know what they say: If it is good enough for Leno..................... http://www.marineturbine.com/motorsports.asp .

David