My factory muffler started rattling so I pulled the end cap off to see whats what. I found that the center divider had a crack in it and since I am king of the mig welders I welded it back up. I also romoved the inlet cone and screen and the outlet screen so there is less restriction. The wierd thing is after running it for a while it I noticed it is still just a quiet as it before and has even more top end. Should I change maps . I really like the Speed map but dont want to run it to lean. I mostly trail ride at WOT.

 

The Speed map will be just fine for ya. Can you do a dwg of what you did? I'm very interested.

 

Its very simple , slide muffler off headpipe. You can leave the headpipe on the quad. Remove the hex screws on the end cap and slide out. I used a small cut off wheel to cut the inlet cone out . The center baffle seemed not to have enough welds on it which is probalbly why it cracked. It also supports the mounting bolt hole so I wouldnt recomend removing it. I welded the baffle in with much more than the skimpy tack welds . I also drilled four half inch holes in the baffle plate for more flow. Reassembled and Tada more ponies for no money .
I still dont quite understand why it so quiet because its basically a straight through exhaust system.
On other thing ,I would not weld to much at one time and keep cooling the area with a wet rag to keep the chrome from discoloring.