Bonneville America Forums Forums Technical Forums Exhaust "Ringing" Gutted stockers

Gutted out my stock pipes I had laying around for years, I like the sound, loud,deep, but I was concerned about back pressure so I cut and welded the last inch or two of the stock baffle, basically a 1" hole about 1 1/2" from the end of the pipe. This set up makes a awful ringing (for lack of a better description) sound on acceleration, any thoughts or suggestions on how to correct this would be greatly appreciated.Thanks, Craig

You'd need another baffle halfway between where the can widens and where the current one in order to disrupt the resonant frequency. This is pretty much how the stockers work. Best course of action is to remove them, in my opinion.

Empty pipes just sound crappy. You need some sort of baffling in there to take away the ping. I ran my Scepter pipes with no baffles once and it sounded terrible. Loud and low but the ping was awful.

Whistle tips! Whooooooo whooooooo

Mine did that with a lollipop baffle.

lol Bub Rub

For best performance you want the back pressure at the same spot as the stock. This is called the tuned length (from the exhaust port) and has been calculated by the Triumph engineers. Moving it a little bit will change where the peak torque is in the rev range. Moving it a lot or not having a restriction (for back pressure) at all will reduce performance. It is usually near the front of the muffler (I haven't looked inside the stock pipes).

Sound ... your empty case is now a megaphone and the metal wall reflects and amplifies the high pitch (pinging). For best audio results you want some sort of lining inside the muffler like muffler grade fibreglass or stainless wool. This muffler can still be "straight through" for loudness but the glass or wool absorbs most of the short wave (high pitch) and some of the other frequencies. Of course you will need a piece of perforated tube inside the muffler to keep the glass in place.

stock pipes I have gutted sound great. They have a mesh liner that can and should be left in place. I also leave the reducer cone in the front of the pipe for back pressure.

Thanks for the great info guys, thinking of going with some type of after market baffle. Can you recommend one that creates some decent back pressure and still be on the loud side. Thanks again

J&P Cycles for one but you can get them from most after market sellers.

Thanks Dog33, do you know if theres anything that could be used in place of the reducer cone since that is long gone ? I've tried some old baffles from the exhaust end of the pipe but still get some ringing, thinking maybe trying something from the inlet side of the pipe ??

Something like this would probably do the trick for you.

Dang your quick, thanks. I'll Order now and hopefully have em by the weekend.

I've gutted my pipes completely and inserted Sportster baffles in the front..tapped them in, screwed them down, she sounds great with good back pressure.

It's not the best pic but this is all I can provide. Simple cheap sportster baffle off fleabay for around 3-4 bucks each, completely gutted pipes (sucked...every baffle was welded). Shoved them down into the throat, drilled a small hole underneath the muffler and bolted her up.

Thanks for posting the pic, how long are those baffles?

Hummm...I think they were 4 1/2 inches. Been a long time.