Re: muffler gasket blowout
I have no problems with these, and don't even bother to replace the studs with stronger ones. When an engine is new, I fire it for a few minutes on the bench, cool it down, fire it again, and so on 4 0r 5 times. During these runs, I do not use the muffler hanger, so that the muffler will shake a bit to compress the gasket nicely.
When this is done, I tighten it and then add the hanger.
Then, like with the motor mounts, I check tightness before each ride for first 40 miles or so, then deliver to customer.
Sometimes I sets and thinks, sometimes I jes sets.