RE: Ys 91?
That's a great point, DadsToysBG - the fact the Y.S. is pumped means that you don't even have to run any muffler because the tank pressure isn't dependent on it. You can run it with only the header if you want!!!
Jmoga - that is a nice install... I guess 4 stroke inverted is the only way to go for the WM MM!