Rust inside left slip on muffler
Stellar HDF Member
Joined: Jul 2021
Posts: 2,088
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From: NoVA
As many pointed out left one doesn't get hot enough, cause it gets less flow, especially at low RPM. Catalytic converter has nothing to do with it. Just wet it with evaporust, hit it with steel wool and then keep an eye on it.
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Tourer
Joined: Jan 2011
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Exhaust
This was after a 3 hour ride. Happens every ride. I will wipe out the rust and after the ride it's back. Lots of water out of that muffler. Any ideas? I still think it's the cat.
Last edited by slider1156; Feb 24, 2026 at 01:32 AM.
Seasoned HDF Member
Joined: Jan 2007
Posts: 5,604
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From: Virginia
Nope, its caused by condensation sitting in the muffler as others have said. If you dont want to change to a TD system or swap mufflers, you have couple of options. Some riders will drill a small hole on the underside of the left muffler to help the condensation drain and/or you can hit the inside of the muffler with high temp black spray paint. Of course, you can also keep wiping it out as well.
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Grand HDF Member
Joined: Aug 2014
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From: Eastern Ohio
Nope, its caused by condensation sitting in the muffler as others have said. If you dont want to change to a TD system or swap mufflers, you have couple of options. Some riders will drill a small hole on the underside of the left muffler to help the condensation drain and/or you can hit the inside of the muffler with high temp black spray paint. Of course, you can also keep wiping it out as well.
Stellar HDF Member
Joined: Mar 2020
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From: West Coast
also vote for black paint + a tiny hole. But seal the hole so it does not rust out. possibly drill the cross over and not the slip on. They are a dime a dozen on fleabay, slip ons not so cheap.
Last edited by Taxgod4u; Feb 24, 2026 at 12:40 PM.
