Allow me to correct my previous post. The OS's I own do not use a gasket. I have two .46's, one 50, two .75 AX's, three 1.20 AX's, and one 1.60 FX and none use an exhaust gasket. They do not leak, nor do they come loose if tightened sufficiently.

I also had a Super Tigre 75. That had different problems with the exhaust system. I won't go through that, but I eventually replaced the muffler with a MACS header and tuned pipe. And, I don't recall a gasket on that engine either and it neither leaked nor came loose on me.

CGr