Dar, I wish you had not made that post. Now I have to go rethink two of my planes. I have one on a muffled YS61LS two-stroke and one on a Rossi tuned pipe installation. Picture is of the current YS installation. I don't have one of the tuned pipe Rossi. But here is one of the pipe installation prior to switching the engine from Webra to Rossi. The pipe now has the same type deflector as the YS61 shown.

The blue line that looks like it is going down to the muffler on the YS is the fuel vent line from the tank. It is not connected to the muffler.