RE: Muffler gasket
The muffler bolt (the through one) on the 1.20 AX on my Excelleron 90 broke in flight. We were lucky enough to find it on the ground after it came apart. When it did, I shut down and did a dead-stick landing. The bolt was snapped right at the beginning of the threads.
OS sent me a new bolt and a pair of ny-lock nuts.