My 500i did the exact same thing as yours is doing, the solution for me was easy. The carb vent hose was being pinched by the seat when it was latched. I cut some off and re-routed the the vent hose and presto, no more problem.

 

Just Pick out a spot and cutt.
I cutt mine a little shrter than half. i have only 2 baffels in it. You will see an increase in power just by unclogging your holes.

ALSO

BE SURE AND CUTT THE EXCESS PIPE THAT EXTENDS ABOUT 1 1/2 INCH UP INTO YOUR MUFFLER. THIS LITTLE BIT OF EXCESS WILL NOT ALLOW THE MUD AND DEBRIS TO FULLY DRIAN FROM YOUR EXHAUST. CUT IT WITH A TORCH. YOU CAN LEAVE THE PART COMMING OUT OF THE BOTTOM, OR DO AS I DID AND MAKE YOU ANOTHER ONE COMMING OUT OF THE END CAP.

 

thx as always. my muffler is different then the new ones. But im sure i can make a mess of it. Took the day off work, maybe ill cut it up this afternoon.

 

Vewdew- What Catkrazy said is correct. It will not be much louder at all, just a little deeper tone. I did not have to rejet but I also put on an axhaust snorkel at the same time.

 

Another question for all you, what if I cut out the little piece where the exhaust comes out, weld something over the little hole and then cut a bigger hole straight out the back and leave the inner tube alone, would that work, or is the best solution to cut the inner tube down??

 

I cut my inner tube in half and also blocked off the factory down tube. Then I drilled a 1.5" hole in the center of the rear cap and welded on a 1.5" exhaust pipe straight out the back. The inner tube is what needs to be cut as it is very restrictive. I don't think you will see any difference if you do not remove some baffles.

 

One more related question, I am doing this muffler thing tonight and thought of something else, when I put the inner tube back in, where do I place it?? Near where the exhaust comes into the muffler or near where it exits, or does it matter where it goes?? Thanks a lot. Also wouldnt I want to put a bigger jet in after I do this?? Daveb said to try a 148, but wouldnt I want to go bigger that stock instead of smaller?? Or should I just try the stock and watch the plug colour?? I am also going to change the preload on my clutch spring, I need more power, I was getting my a$$ whooped by an outlander the other day.

 

Hey doob, ya i dont know the answer to the replacing of the inner. Thats what i was trying to get out of ODB hehe. Id bet your way rich now, like the rest of the stock bikes. Get a new plug if possible and leave the main and test it. It might be perfect. If im not mistaken a smaller jet will be leaner on the main. I went to a 142 on the main (no muff mod and its clogged) Made the plug look real good and gained more power in 2nd gear with the Gators. But i think after the mod ill have to go back to the 145.

 

[quote]
Originally posted by: doober
One more related question, I am doing this muffler thing tonight and thought of something else, when I put the inner tube back in, where do I place it?? Near where the exhaust comes into the muffler or near where it exits, or does it matter where it goes?? Thanks a lot. Also wouldnt I want to put a bigger jet in after I do this?? q]

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I tack welded the inner tube back in about 2" from where the exhaust enters the pipe. I ended up getting the best performance from my stock 148 jet, I only had to adjust the pilot jet to get it to idle correctly.

The 400 will probably respond differently, you will just have to play with it till you get it right.

 

Thanks a lot ODB and everyone else, I have an automatic tranny I dont know if thak makes any difference or not but i would imagine it doesnt. Will let you know how it turns out for me.