Modifying your stock muffler steps with pics and video

I like the lack of sound that the stock exhaust makes, so I thought I would see what it would do with some help. I also like the concept of the EXUP, makes sense to me so I did some work...

1. Take the stock muffler chop it in half below the weld. However, take a straight edge and draw at least two lines on it and make a couple marks with measurements. That important when you go to put it back together. The thickness of the blade will take material out of the overall length, and I wanted to reuse the factory heat shield.

2. Using an air chisel I removed the honeycomb catalytic material.

3. The muffler chamber itself has an inner tube that looks like what I would call a strainer. Using a 1.25" hole saw and extension I bored the top of it off to essentially bypass it.

4. To keep the muffler the same length, I rolled a piece of flat stock material to act as a backer for the weld. The two halves of the muffler should be separated by approximately the width of the blade I cut it with. A few tack welds internally to keep the backer in place.

5. Put the two halves together. Line up your timing marks, make sure your gap is consistent, few tack weld around the can to keep it from shifting.

6. Finish weld.

7. Reinstall.

8. Took me about an hour or so.

If you're on a budget, I figure it would save you the cost of a muffler and the EXUP dongle.

Sounds pretty close to stock, slightly deeper. Retains the EXUP and the factory look, and factory heat shields.

a video of it running would be nice

I know right? I'll do it today.

Funny thing is, my hearing is wasted so there is a chance that it sounds totally different and I can't tell.

sounds good

I honestly can't tell if it sounds different now.

However, I did go riding today and it felt pretty good. I was hoping to get a little more on the bottom end.

Do you still have this setup? Did you setup with a fuel programmer as well? How is the performance?

svandell wrote:

Do you still have this setup? Did you setup with a fuel programmer as well? How is the performance?

I still have the setup but my wife has been riding the WR. I didn't use a fuel programmer with it until later when I did some air box mods. I would say performance wise, it's decent. Sound wise, I think the bike is still pretty quiet, and it also retains the stock heat shield if you're using any type of side bags.

For what I do with the bike, it's an easy no cost mod. I think you could improve it slightly by opening the internal baffle a little more the exhaust tip.

Jerry