Playing around one day, I stuck a lawn mower muffler on a heater hose and pressed it to the muffler of a chinagurl. Awesome sound. Today, I went to fix a bad exhaust gasket and the hose and LM muffler were still hanging there. I had an old MB muffler so I cut the L off and put the heater hose on it. Didn't work well at all! snork. But does have a funky sound and I might retry this. (took me months to try this time) Much better low end but had all sorts of leaks fixed by the time I tried the hose. If any thing, a decrease in top end. Only cool part so far is the sound and ease of leading the "pipe" Have it ziptied under the BB. 2 Door asked me if I could smell smoke. Ayup!, and it would melt if kept this way. On a full muffler, it makes a "Thump, thump" sound. As is, is just loud 2stroke MB but when you let off the gas, it grumbles like a MC.
Gonna redo it in the morning. Here is a vid for sound, but just sounds like a 2 stroke at low revs.
mufflermodvid.flv video by dan3xd - Photobucket
(is just play and seeing what can be done with junk parts)