Don't bother. I'm just thinking about what might fit within the width of the frame, would flow well, be at least somewhat quieter than a straight pipe, and not blast your leg with hot exhaust. I have most of that figured out. I'm thinking an aluminum pit bike muffler (straight through, not quiet but not as obnoxious as a straight pipe) or a hotdog type muffler (but larger than what most people use, one made for a larger engine, less restriction than a smaller one) mounted transversely (side to side) under the seat. The pit bike muffler I have is about 9.5" long and a little less than 3.5" in diameter, which I think could work with a couple of tight bends to get into the inlet. A steel hotdog type muffler would probably be easier. Either one would be blasting exhaust out the right side without some sort of deflector or a bent tube on the end. I'll give it some more thought. I