Stock exhaust mod

[Bikedad1]

Has anyone taken the stock exhaust apart and removed the innards and us it as an expansion chamber? I am currently trying this with a old stock exhaust that I have and I intend to find a muffler to put on the snout of the exhaust to quite it back down. I looked inside of the "expansion chamber" of the stock pipe and couldn't believe what I found......a perferated outgoing pipe, a solid return pipe and 4 baffles........how is that supposed to work as a expansion chamber when it is full of stuff that will not let the sonic wave move back and forth! It is just a 4-stroke exhaust slapped on a 2-stroke!

 

[Bikedad1]

OK so I cut the thing apart and removed ALL of the innards then welded it back up. I am pleasantly please with the results. I actually has power band now, from about 15mph to 25mph it stays in power band and pulled me up 12% grades at a comfy 22mph. It is louder for sure and when it is under a light load the 4-stroking is loud! I plan to find a suitable muffler to fix that soon but for now it sounds like a dirt bike.

 

[Cabinfever1977]

i thought about doing that a long time ago,but i dont have another muffler to mount on the end.

 

[matt167]

i thought about doing that a long time ago,but i dont have another muffler to mount on the end.

Briggs and stratton replacement muffler for engines under 5hp. should have 1/2" pipe thread.. $5 from walmart

 

[Bikedad1]

Nice I will have to take a trip to Wally Mart.