I noticed there have been some owners putting their Vance & Hines S4 Stainless bolt-on mufflers up for sale because they were too quiet . Here's a quick easy fix I just finished . Not many bolt on mufflers sound this good to my ears after modding and it's mainly due to lack of a chamber built into them like what's incorporated into the Vance & Hines design .
Disclaimer : Do so at your own risk . The pair I bought used already had some stripped cap screws that hold the exit tips on . I had a few spares from last time I modified a set of these mufflers . I just ground a slot with a small cut-off wheel then removed with a common tip screw driver .
Look down through there . The perforated flutes you see are inside the OEM midpipes . The chamber is on the inlet side . From what I've determined , the chamber s what gives the deep tone at idle . Only ART and a couple other manufactures use these chambers that I know of .
View attachment 1141262
Here you see these have a removable baffle but the hitch is they use a decible killer inside . It's just tack welded though .
View attachment 1141263
Packing removed
View attachment 1141264
The exit cap and perforate tube are held together by three bolts .
View attachment 1141265
View attachment 1141266
Here is the decibel killer thats tack welded in two places .
View attachment 1141267
The baffle " 3rd pic has an inlet of 1.400 inside diameter . I cut mine off just aft of that inlet where it expands to a 2.250 muffler core diameter . Then I cut the DB killer welds and knocked it through , re-wrapped the packing and tightend the clamps and re-assembled .
Hope this helps some of the owners that hear nothing but chain on the hi-way . Or I should say race track . I assume this an illegal mod and for racing purposes only . Sure made my race bike sound better
Disclaimer : Do so at your own risk . The pair I bought used already had some stripped cap screws that hold the exit tips on . I had a few spares from last time I modified a set of these mufflers . I just ground a slot with a small cut-off wheel then removed with a common tip screw driver .
Look down through there . The perforated flutes you see are inside the OEM midpipes . The chamber is on the inlet side . From what I've determined , the chamber s what gives the deep tone at idle . Only ART and a couple other manufactures use these chambers that I know of .
View attachment 1141262
Here you see these have a removable baffle but the hitch is they use a decible killer inside . It's just tack welded though .
View attachment 1141263
Packing removed
View attachment 1141264
The exit cap and perforate tube are held together by three bolts .
View attachment 1141265
View attachment 1141266
Here is the decibel killer thats tack welded in two places .
View attachment 1141267
The baffle " 3rd pic has an inlet of 1.400 inside diameter . I cut mine off just aft of that inlet where it expands to a 2.250 muffler core diameter . Then I cut the DB killer welds and knocked it through , re-wrapped the packing and tightend the clamps and re-assembled .
Hope this helps some of the owners that hear nothing but chain on the hi-way . Or I should say race track . I assume this an illegal mod and for racing purposes only . Sure made my race bike sound better
