When I initially installed my Roadhouse exhaust on my '98 Honda Shadow Aero, I loved the look of the pipes and sharkfin tip, but wasn't too impressed with the sound. A little hollow, almost like the exhaust was muffled by a pillow. The sound also seemed to reverberate and collect in the chamber created within the sharkfin tip, further softening the sound.
Below are some simple modifications to give the exhaust an angrier sound, more like a hammering growl. The mods are easy to do, so do a little experimenting.
You will need:
7-1/2"x8" or larger piece of HVAC sheet metal
five 2" screw-drive hose clamps
approx 1 ft long 2"-diameter muffler pipe (got mine for free from scrap pile at local muffler shop)
Allen set, screwdriver, pliers
1.) Prior to disassembling you muffler, use a tape measure to find the distance from the end lip of the baffle core to the end of the diagonally-cut sharkfin tip. This should be approximately 8" at the top, and 6" at the bottom. You will need these measurements when you cut your extra piece of muffler pipe to extend the internal part of the pipe through the sharkfin tip. (We'll get to this later.)
2.) Remove your baffle core by removing all three Allen-head screws at the end of the exhaust cannister, removing the sharkfin tip, and pulling the core assembly out, either by hand or grabbing it with a pair of pliers. You will see this-
3.) The baffle material is two layers- a thick fiberglass insulation wrapped around a thin open-weave material. You should remove this by pulling the masking tape wrap from around the insulation. This will expose the baffle core. (*Please note that these pictures are from my exhaust after I had run several hundred miles on the modifications, so take into account the heat-induced color changes in the following pictures.) -
4.) Next, take a piece of HVAC sheetmetal (I purchased this piece for $3 at the local hardware store) and cut two 3"x8" strips, using a tin snips. While you're at it, cut a 1-1/2"x8" strip, to be used later.
5.) Take the 3"x8" strips and wrap them around the baffle core, one at each end of the perforated section of the core, fastening them snugly with four 2" screw-drive hose clamp. (This picture doesn't show the coned-end wrap very clearly, as the heat has discolored the sheet metal and one of the hose clamps.) This will effectively leave you with about 4" of exposed perforated baffle.
6.) Next, you will need a hacksaw to cut the extra piece of 2" muffler pipe diagonally, using the measurements made earlier. (See #1.) Use a round file to smooth the cut edges.
7.) Take the 1-1/2" strip of sheetmetal, and fasten it loosely around the outlet lip of the baffle core with a hose clamp. Put the straight end of the diagonally-cut piece of muffler pipe flush against the lip of the baffle. Tighten the hose clamp so that it is centered on the seam created by the baffle core lip and the pipe extension. Tighten very snugly. Make sure you have the pipe extension rotated so that the long dimension of the diagonal cut is at the top, and the screw hole on the end of the baffle core is at the bottom.
(The first picture is the 1-1/2" strip loosely held by a hose clamp, prior to putting it in place. The second picture illustrates the bottom screw hole of the baffle core.)
8.) After the pipe extension has been added, rewrap the two layers of insulation material around the core, and wrap firmly in place with masking tape. The finished assembly should look something like this-
9.) Reinstall the modified baffle core into the exhaust cannister. Make sure that the pipe extension is firmly in place by attempting to pull the entire core assembly out by gripping the pipe. If it loosens, it'll probably come off going down the road, so retighten accordingly. Reinstall the screw that holds the baffle in place.
10.) Replace the sharkfin tip using the remaining two Allen screws. The view up the pipe will look like this. (You can barely see the end of the pipe extension.)
11.) Wash your bike and polish the chrome, so your bike looks as good as it's gonna sound!
Other variations in these modifications that I have gleaned from the forums on the net include:
-Completely covering the perforated portion of the baffle core, either putting the sheetmetal directly against the baffle, or putting the thin burlap-appearing layer under the sheetmetal wrap. (Makes the pipes louder.)
-Leaving the insulation material completely out, while completing some or all of the other mods.
-Only removing the insulation, without any other mods.
-No pipe extension.
-Some have used Coke cans as a baffle wrap. (I used to do this to my car's exhaust pipes when I was a broke teenager. Seems to me that those coat hangers made great muffler hangers, too.)
Please note that the use of a strip of sheet metal and a hose clamp to attach the pipe extension is only temporary. You will need to have it welded if you like the sound it creates. If you don't, remove it.
The original ideas above were from RoadHouse tech department. They will sell you the 3" pipe wraps and clamps for $20. They are working on the pipe extension for inside the sharkfin tip, as above, but they tell me it won't be ready until August. (I'm a little disappointed that the RoadHouse pipes need these modifications, but that's life.)
I rejetted with the FactoryPro jet kit, using #175/#180 mains, #45 slow jets, and position-3 needle clips. I also used a K&N high-flow air filter. Midwest elevation. I have better performance than stock, and absolutely no deceleration popping. (Might consider the #178/#182 mains if you completely block out the baffle.)
My other baby-