Rotaries do kick ass, but as noted only in the hp per cid dept. every thing that has been said so far is true. Let me add that the burn alot of oil too. The damn thing are almost like 2 strokes!
Norton built a rotary motorcylce racer in the late 80's. Succssful at the Isle of Mann TT race. Also they are also used in Milliary Drone aircraft (target practice).