Author Topic: Best ideas for sealing enhaust noise at header pipe?  (Read 338 times)

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DavidGraves

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on: September 18, 2020, 02:04:10 am
I have a 2006 Iron Barrel Bullet with an aftermarket header and muffler that I did not install.

In my efforts to quieten the muffler the header noise has gotten stupid worse.....pop pop pop pop pop pop pop pop

I would appreciated any best practices to quell the noise at header........

David Graves


AzCal Retred

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Reply #1 on: September 20, 2020, 02:39:37 am
PaulW asked a similar question in "Securing a "push in" exhaust." a few months back - it's found about 5 pages back now.

I posted this describing my fix, as well as some pictures a couple responses later -
>>I've had luck sealing the exhaust using the chromed steel finned 1 3/4" "Exhaust Pipe Cooling Ring"; Hitchcocks PN# 26281, and a twisted loop of #10 fine stranded copper electrical wire. I put the cooling ring on the pipe, secured the pipe, twisted the wire around the pipe between the ring & the head, then tapped the ring up against the flat face of the exhaust port. I cut the "tail", the twisted portion of the copper wire, to about 1/2", then aligned it with the open split of the ring. The stranded copper seems to fill irregularities adequately and really restricts the amount of blowby, absolutely better than the plain pipe. Sealing a plain straight wall pipe into a straight wall hole seems doomed to fail, you'd need some sort of packing/gasket material and a way to secure it; the OEM installation has nothing. The cooling ring gives you an adjustable backstop, and the fine stranded copper wire has enough "smoosh" to take up the gap. The steel ring has held up well as opposed to the alloy ring which blew up on the first tightening. The Bullet isn't exactly a featherweight racer, so steel is good enough for me and my 22 BHP iron steed. <<

Basically you end up filling the gap between the cooling ring and the cylinder head exhaust face with multiple wraps of fine stranded copper wire, then tapping the ring to squish it up against the head, thus forming a copper packing. No chemical bonding issues or cure times needed, & when removal time comes there's nothing to scrape off. I used some 19 strand #14 I had lying around, just stripping off the outer jacket from 3 feet or so of wire, wrapping it multiple times around the pipe, then twisting the ends to tighten it up. The gap in the cooling ring is a convenient place to tuck in the "tail" you've twisted together when tightening the strands. Total cost is some scrap wire & a $12 steel cooling ring.

This works well for me, eliminating the popping when descending a grade using engine braking or rolling up to a stop sign. If the pipe shifts position, you just tap the ring back up snug to the head again. - ACR -
A brace of 1999 Bullets: 1 Red Deluxe, 1 Green Standard. Also, 1 wee orphan 1956 Fire Arrow project.


Karl Fenn

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Reply #2 on: February 22, 2021, 10:56:37 pm
I have had good success with the expanding paste, expands to make a seal when it gets hot, over the years l have used many things including tin foil and copper wire, on the BSA C15 they had no nuts on the head manifold paste used to work fine l have even used it on my BMW bikes never leaks and works.


Karl Fenn

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Reply #3 on: February 22, 2021, 11:06:41 pm
Of course one important thing to note if you get pop back on your exhaust system sounds like back fire the most probable cause is an air leak in the system as the burnt gases flow at speed they create a vacume which sucks in air and ignites unburned fuel in exhaust.