back when I had my m109r, I drilled holes around in the backplate of the mufflers, but wound up not liking how it sounded. then I used stainless steel bolts with toggle spring wingnuts to close up those holes.
on my street 750 I again drilled seven 1/2" holes around the back plate.
it did deepen the sound, and I was pretty much pleased with the sound.
when I was able to afford it, I got the firebrand loose cannon and it was too loud for my taste...then I got their db killer baffle in it...and wow!...love the sound now!
A forum community dedicated to Harley Davidson Street owners and enthusiasts. Come join the discussion about performance, classifieds, modifications, troubleshooting, maintenance, and more for the 750 and 500 models!