I changed the exhaust to a quieter one for SM riding (don't know what brand/make, got it with the bike), also the header pipe, and noticed that there is no gasket, or it's a lot thinner than the gasket on the original one between the header pipe and the rest of the exhaust (slip-on muffler on pipe). Can this cause excessive popping? It's not like popping 2-3 times louder on decel, it's popping continuously like machine-gun fire Or mixture problem? (Put Hot-Cams exhaust cam, but didn't adjust anything in carb). What can I use as a replacement gasket? Is it something Yami specific, or can I get it from automotive stores also?