A common problem of aftermarket mufflers is the tendency to come loose after only a few flights.
These tips not only help with the Bergen Muffler, but can also be applied to some of the other aftermarket mufflers.
Your Bergen Muffler comes with the muffler body, 2 studs, 2 lockwashers, and 2 nuts.
The first and most important thing to do is to clean the exhaust port of the cylinder head.
It should look like this when finished. Some Scotchbrite helps to get the difficult stuff off without scratching the surfaces.
Here's the secret, use red RTV as a gasket AND as a loctite for the studs and nuts.
Put some Red RTV on the studs, then screw them into the cylinder head.
Thread them in far enough to leave room for the washers and nuts with the muffler installed.
Using your finger, put a thin layer of Red RTV on the muffler face.
Place the muffler over the studs and install the lock washers.
Dab a small amount of RTV onto the studs.
Then install the nuts.
It's may be helpful to use a modified wrench, either 8mm or 5/16th works.
Tighten them suckers down!!
After the first flight, while things are still hot, go ahead and snug the nuts down again.
WARNING!! THE MUFFLER GETS EXTREMELY HOT AND WILL BURN YOU VERY QUICKLY IF TOUCHED.