Philly, this old post should give you a general idea of how I attach a muffler to a stock header.  My bike uses a Mac header which is significantly different.  It's much easier to fit a muffler to the Mac header because the header is straight and does not have a step that reduces the OD.  In the old post, I show how to fabricate an adapter and shim it to fit the stock header.  It's not too hard but you will need a MAP Gas torch and a bench vice along with other basic tools.  See replies #3 thru #20 of this old post.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1623048749

so -- funny story. I started brazing together my own mid pipe adaptor as DBM outlined in the post he shared. First time brazing and I decided to set up my brazing station on my back patio -- my plastered back patio -- a material I know have come to understand does not enjoy high, direct heat being applied, due to a phenomena known as "spalling", in which moisture trapped under the surface needs to expand when heated past the boiling point.... Violently.

Baseball sized chunk of plaster exploded directly into my face. Fun times.  

Anyway I did get the shorty cherry bomb on there eventually, and found it too open. Back to the drawing board.

Surviving Philly wrote on 08/03/25 at 04:52:48:


Or back to STOCK.

On my older LS this is the exhaust I fabricated and am very happy with as to performance and sound. It is a VooDoo slash cut muffler. I built the interface to header with a baffle in it and installed a "bolt in" catalytic baffle inside the muffler at the rear.

I built a mounting bracket to position the muffler as a 3/4 down turn, rather than exhaust exiting at 90 degrees. This repositions the exit of the  exhaust down rather than out at side which substantially changes the sound.

The adapter is just exhaust pipe from Napa, I took it to muffler shop and had them bend it and then expand it to fit header. The smaller cut lines are to allow for greater compression in fit utilizing a thin sheet steel sleeve to assure seal.

It is much more free flowing. You could add a bit of back pressure by through bolting a fender washer onto the catalytic baffle to force gas around it at the exit. I have run this set up for 6 plus years and am very happy with it.

On my S40 I have the Delkelvic exhaust and it is different. That bike has a more "2 stroke" feel to it, as best I can describe it. I was not completely happy with the look of it out of box and built a new mounting bracket for it to rotate the muffler. I added a catalytic to the rear of it also to improve the sound and add a bit more back pressure which helped minimize the feel of it. Thought though is it needs a bit more back pressure.