I have mounted a repop stock muffler from David Silver Spares onto my stock header collector and have noticed exhaust blowing out from the connection. The collar seems be simply a crimp fit around the muffler with a bolted connection...I've tightened it down all the way but clearly it's not an airtight joint. I don't see a gasket of any kind in the parts diagram.
Anybody have a similar experience and/or some advice for me?