I found my exhaust port finally clogged up from all the lugging I did while pulling trailers.
I cleaned the stock muffler out by soaking it overnight in a bath of penetrating solvent, but I still wanted to swap to a less expensive muffler with a welded-on exit pipe ("bleed tube") and save the fancy one for my all-stock engine.
I found these generic scooter mufflers to match the bolt pattern, and they have exhaust holes just slightly bigger than the motor exhaust port. The flange is big enough to cut the gasket a hair bigger than the port, and smaller than the muffler hole, or to match the muffler hole if you want.
The stock gasket got re-used, but cutting off the used portion and making a new gasket. It was a pain in the butt! 3 layers of rubber and 2 layers of metal. I dulled up two razors tracing and cutting it. I used 3 bits to step out the mounting holes to prevent tears. I used chainsaw files (flat and round) to carve out the muffler hole to a nice shape with the flat sides and rounded corners. I had to lock some 6mm nuts on the stock bolts and shorten them a little to prevent them bottoming out on the "jug".
I recommend getting high grade all-thread or studs (not happytime hardware) and using lockwashers and nuts. Then you can swap mufflers or clean out your exhaust port in the future without wearing the threads.
Photos follow, of engine without muffler, muffler comparisons, muffler mounted, cage mounted, cage trimmed and mounted to not block new muffler exit pipe.
I cleaned the stock muffler out by soaking it overnight in a bath of penetrating solvent, but I still wanted to swap to a less expensive muffler with a welded-on exit pipe ("bleed tube") and save the fancy one for my all-stock engine.
I found these generic scooter mufflers to match the bolt pattern, and they have exhaust holes just slightly bigger than the motor exhaust port. The flange is big enough to cut the gasket a hair bigger than the port, and smaller than the muffler hole, or to match the muffler hole if you want.
The stock gasket got re-used, but cutting off the used portion and making a new gasket. It was a pain in the butt! 3 layers of rubber and 2 layers of metal. I dulled up two razors tracing and cutting it. I used 3 bits to step out the mounting holes to prevent tears. I used chainsaw files (flat and round) to carve out the muffler hole to a nice shape with the flat sides and rounded corners. I had to lock some 6mm nuts on the stock bolts and shorten them a little to prevent them bottoming out on the "jug".
I recommend getting high grade all-thread or studs (not happytime hardware) and using lockwashers and nuts. Then you can swap mufflers or clean out your exhaust port in the future without wearing the threads.
Photos follow, of engine without muffler, muffler comparisons, muffler mounted, cage mounted, cage trimmed and mounted to not block new muffler exit pipe.
