CallMeBlunt, i believe i use something around 3/4 to 7/8 tubing and just ran the tubing into the tailpipe and there inside the tailpipe is where i made the muffler. real simple to make. works great for low hp motors and sounds good. just like a vintage minibike should sound:thumbsup:........
just drilled 4 holes straight thru and then again on the side. making a total of 16 holes and then cap it off on the end so the exhaust would only exit out the holes.
also use a round plate with holes drill in it, has a baffle. as a option you could pack it lite with corse stainless steel material:shrug: i have gone both ways and not really sure if it makes a differents:shrug:
find a place where you think you want to put the round baffle and drill couple holes. set the baffle inside the tail pipe and center it with the holes and spot weld it into place. go back and grind off the extra weld and then give it a brush finish so any high temp paint can stick to the metal.