Rotary valve has recently come back into vogue, at least in GP125. The latest series of Aprilia 125 factory racers have rotary valve induction. The idea is that when properly tuned, it can produce just as much power as a reed, but with more torque at higher rpm. I think kriedler's 80's GP50 bikes were rotary also. I wouldn't bother trying this with an AV10, as theres already plenty of power potential, but maybe an AV7. The ignition can be resolved by using an internal rotor flywheel.