Eliminate the Muffler
So I realize that I'm relatively new to the world of motorbicycling, but I'm fairly well grounded in thermodynamics. What I'm getting at is removal of the muffler on my chinese kit engine to maximize efficiency. The only down side that I can think of would be the ridiculously loud noise as I roll down the street. If you think about it, this might a) create awareness for cars and b) make my bike sound like a real motorcycle. Of course there is the Police factor, but we'll cross that bridge when it happens.
Also a straight pipe exhaust may be an alternative to no muffer at all.