I read your instructions again and one thing you mentioned got me thinking. You mentioned you used a Milwaukee 1" deep hole saw. You also mentioned you can't weld the inner support.

How deep is this 1" deep hole saw bit you used?
Does this deep hole saw bit drill the outer and inner support?
Is it the inner support you thread the iron pipe to?
Did you also drill the 1st baffle to 1"?

I am assuming that there is chamber between the inner and outer wall around the exhaust outlet. I bought a normal 1" hole saw bit, but you got me thinking it's not what the job requires.

Better get it clear before I start cutting.

Thanks SH

 

Shaun:
See reply's below

How deep is this 1" deep hole saw bit you used?
Approx 3"

Does this deep hole saw bit drill the outer and inner support?
Yes this allows you to thread in the new pipe.

Is it the inner support you thread the iron pipe to?
Yes, this is the support or baffle about 3" in from the end.

Did you also drill the 1st baffle to 1"?
Yes, I also drilled the next baffle to 1/2". I used a 12" x 1/2" bit for this.

Here is the post with the photo's when I did the stock muffler mod.
https://www.kawasakiforums.com/m_36561/tm.htm

Note: I drilled the inner baffle to 1/2" after this mod.

Hope this helps!

Don

 

Shaun:
See reply's below

How deep is this 1" deep hole saw bit you used?
Approx 3"

Does this deep hole saw bit drill the outer and inner support?
Yes this allows you to thread in the new pipe.

Is it the inner support you thread the iron pipe to?
Yes, this is the support or baffle about 3" in from the end.

Did you also drill the 1st baffle to 1"?
Yes, I also drilled the next baffle to 1/2". I used a 12" x 1/2" bit for this.

Here is the post with the photo's when I did the stock muffler mod.
Note: I drilled the inner baffle to 1/2" after this mod.

Hope this helps!

Don

 

I did this mod as well only mine was more the way vfrpilot did his.

-The first step was to remove the stainless steel band on the outside of the muffler by grinding away the welds that hold it on.
-The next step was to band saw the end cap off thru the weld that goes around it.
-Next remove the two spark arrestor plates, the 2nd one is the one everyone has been drilling out to 1/2'.
-There is another plate yet, deeper inside but I chose not to drill that one but vfrpilot did.
-Next I opened up the hole in the center of the end cap to allow the larger pipe to fit.
-Finally I welded the pipe on the end cap, then the cap back on the muffler, then painted everything with high temp paint and welded the stainless band back on.

Some people might think this is all a big waste of time for virtually no HP gain but it sounds better anyway. Right? The entire proccess took around 3 hrs and I did it in a machine shop where I work so it was pretty easy all in all. I meant to take some pics of the proccess but forgot so I drew some up with my cad cam software, if you were to slice the muffler long ways down the middle this is how it would look.
Sorry for the long post!

the finished product!

 

this pic didnt upload in the post above

[IMG]local://upfiles/1198/CD100B78B7874A0DA8700E36CD283B34.jpg[/IMG]

 

Joel,

Your different variation to the exhaust mod is pretty cool. I like how you added that Cad Cam drawing, pretty slick!
So you removed the two spark arrestors completely right? What did you use to cut them out with?

Why did you not drill the deeper baffle?
How large is the pipe you installed?

You said for sound and visual effects this mod is great. No performance gain at all?


I'm full of questions because right now I am figuring out how I want to do my mod. I have access to industrial mech shop at work. We do have a band saw. I have a plant maintenance worker that does my welding. He has done a couple of small projects for me already. In order to do Dons mod I need to buy a deep hole saw bit and possibly a 12"x1/2" bit for the deeper baffle. I'm not sure about drilling this deeper (3rd) baffle. I hate buying tools for a one time use.

The creativity in this forum is amazing. I love this s---!

 

Nice Job!!
Looks Great!
And you saved your self >$400 in the process.

 

I didnt drill the other baffle because I really wasnt sure about how the sound / back preasure thing was going to work out, you know? Didnt want to mess the thing up and have to fork over the $400 for an aftermarket system. Just not in the budget right now.

The pipe I used was 1 1/8' ID 304 stainless steel. The whole deal was really for looks and to get a little better sound. Performance gain was minimal but I pretty much knew that before I started, but hey I'm happy with the results.

At speed the sound is kind of an "airy" sound if that makes an sense, and upon decel it goes "glub glub glub" not really popping as a lean mixture would indicate just "glub glub glub".