[Masteryota]

The way I see it, with a small displacement 4 cycle engine, you need to very careful about adding a large muffler to it. Most automotive type mufflers have a series of baffles and matting inside to diffuse sound waves. These baffles can make or break an engine.

Typically you want a 4 cycle engine to breathe freely to produce max power, adding some bends and baffles can produce better torque, but the top end suffers if you go too far. I would look into stock mufflers for the smaller quads and trikes, they are mega huge compared to the stock or performance ones for the GY6.

My parents acquired an older B&S 8hp generator years ago, and it had a parts store 'turbo' muffler grafted to a pipe for the exhaust, and while it was quieter than normal, it was a pain to jet properly and it guzzled fuel. Just food for thought.