Does anyone know what is involved in replacing a 2007 s40 stock muffler with an 08 Harley sportster muffler?  ie any major modifications or special parts needed?

I did a search but got mixed results depending on the years of the bikes.  

Installation is do-able but specifics seem to vary most likely owing to the fact that everyone's got a different muffler to try. '08 may not work so well. I think HD has started putting cat's in their mufflers though i dont know when they started. But basically...
1 - get a dyna/sportster muffler with NO crossover and WITH a rail type mount. Get a muffler clamp.
2 - Take off your exhaust (the whole thing). Take off the heat sheild, loosen the clamp, and pull/pry/beat the stock cannon off.
3 - Sacrifice an aluminum can :
  a - Measure the circumference of the head pipe where the muffler will slip on.  Add a little to your measurement. 1/8 -1/4 inch extra should do. That measurement with the extra will be Y
  b - Measure the length from the lip on the head pipe to the end. This measurement will be Z.  
  c - Cut the top and bottom off of your can and cut the remaining tube down the middle so you've got a flat sheet.
  d - Cut your sheet so it measures Y x 2(or 3 or 4)Z.   e - Fold it up evenly so its Y x Z.
4 - Liberally slather hi-temp gasket maker (highest temp rating you can find) on one side of your aluminum can/sheet/strip. Liberally slather the same gasket maker on the inside diameter of the muffler where and to the approximate depth that it slides over the head pipe.
5 - Wrap/shape your aluminum strip around the end of the headpipe with the slathered side down so you can save some mess on your hands.
6 - While holding your strip/shim in place on the end of the head pipe as tightly as you can reasonably manage, slip the muffler on over the shim.
7 - While the gasket maker is still fresh bolt your exhaust back on to make sure your rail mount will line up with the muffler bracket. If it doesnt, turn the muffler until it does. You'll probably only be able to get one hole of the bracket to line up, and thats okay.
8 - Take the exhaust BACK off (i know, i know), and clamp your muffler in place. Wipe away excess gasket maker. Procure a bolt/nut for your rail & bracket mounting and throw the exhaust back on. You're done.

NOTE - I personally did not find it necessary to mount the muffler to the bracket. I did so initially and the nut for the mounting bolt ended up vibrating off somewhere along the line. The muffler didnt actually touch the bracket unless i had it bolted down.It just rested slightly above the bracket after the nut came loose. For a while i left it that way with no issues. I then installed intruder 800 shocks and the change in angles of the muffler vs. the bracket made the bracket useless for its primary intended purpose. I removed it and have been running without it for a while. No issues SO FAR. It could happen one day that my exhaust bolts snap off in the head or the threads in the head get ripped out. If it happens it serves me right but what im saying in a round about way is you CAN eliminate the muffler bracket AT YOUR OWN RISK.

Be warned...if you sucessfully complete this mod you will not stop modding. Its gets costly and time consuming.

The Dyna looks sharp, gives a boost & loses some pounds. Sure otta rejet. No further mods needed.

Well I bought the muffler in the link MF provided, part number 65747-94. It has the sliding bracket. The shipping was more $ than the muffler.    I will follow BurnPgh's instructions he layed out above (thanks BurnPgh). Just need to get the right clamp and some gasket maker.  I also plan to rejet, dont want to dissapoint JOG and just go halfway....but one step at a time.  

BrettKeiselsbeard wrote on 02/12/11 at 04:35:58:




Got nothing to do with disappointing anyone. You change the way it breathes & its gonna be leaner. You Need to rejet, to keep the engine working inside its needed Air/Fuel ratio requirements.

Best place to start for rejetting?

I am replacing the stock exhaust with a sportster. I understand I will need to rejet. There is a lot of info about it and each bike can behave differently so I am seeking a good place to start.

It is a 2007 s40. Only mod I have done is to drill out the idle mix plug and turn to 2.5 out. Only poots on shutdown now.

What I have found so far ....best place to start is the exhaust then the main jet to a 155 and 1/2 the spacer? This will help with the midrange?

Then i may need to re-adjust the drilled out idle mix screw?

Any comments are appreciated.

bill67 wrote on 02/15/11 at 19:07:31:




Do Not reject the idle mix screw. It will get its feelings hurt & get all bent out of shape.