2021 breakout sensor question
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6th Gear
Joined: Apr 2025
Posts: 11
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From: Uk
2021 breakout sensor question
2021 breakout has 2 sensors in the actual silencers.
Looking at changing the silencers..seen 2 ways to prevent the engine warning light coming on.
1.Bypassing these sensors via a tune
2.Cutting the sensor housings out and and welding into the new slip ons.
Also...to save cutting the 2 housings out can these be purchased seperately to weld into the new silencers
(Tab)
Has anyone done either of this ?
Looking at changing the silencers..seen 2 ways to prevent the engine warning light coming on.
1.Bypassing these sensors via a tune
2.Cutting the sensor housings out and and welding into the new slip ons.
Also...to save cutting the 2 housings out can these be purchased seperately to weld into the new silencers
(Tab)
Has anyone done either of this ?
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Joined: Jul 2024
Posts: 99
Likes: 35
From: Ca.
Go to a muffler shop. They usually have to bung a new 02 hole in a pipe. I braze mine in, not weld with a stick. Will never get that hot to melt the braze. I think the thread hole is 18mm x 1.25 pitch. Used for an AFR meter.
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6th Gear
Joined: Apr 2025
Posts: 11
Likes: 0
From: Uk
I'm getting TAB performance silencers...I guess I need to know exactly what size the silencer is in the muffler so I can order the part to braze onto the TAB
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,158
Likes: 11,249
From: San Diego, CA
2021 breakout has 2 sensors in the actual silencers.
Looking at changing the silencers..seen 2 ways to prevent the engine warning light coming on.
1.Bypassing these sensors via a tune
2.Cutting the sensor housings out and and welding into the new slip ons.
Also...to save cutting the 2 housings out can these be purchased seperately to weld into the new silencers
(Tab)
Has anyone done either of this ?
It would be a cleaner install, and easier, to just buy new O2 sensor bungs. Then have a good welder or muffler shop cut the hole and install the new O2 bungs on your new mufflers (silencers) in the same place as on the OEM mufflers (silencers).
Your OEM muffler O2 sensors are part #32700127. I believe they are the smaller 12mm, heated O2 sensors Harley uses. The O2 sensor bungs you will need should have an M12 x 1.25mm thread pitch. If you buy the 18mm O2 sensor bungs, then you will need adapters to fit the 12mm O2 sensors into the bungs. That causes the O2 sensors to stick out of the muffler farther. It could affect the fitment, and many believe it will affect the O2 sensor readings..
Pull one of your O2 sensors out of the muffler (silencer) and confirm the threads size & pitch. I believe you will find them to be M12 x 1.25mm.
Whichever size they are, Harley has used both 18mm & 12mm O2 sensors over the years, it's better to be certain on the thread pitch before buying the new O2 sensor bungs.
Good luck with your mod...
Thread Starter
|
6th Gear
Joined: Apr 2025
Posts: 11
Likes: 0
From: Uk
It would be a cleaner install, and easier, to just buy new O2 sensor bungs. Then have a good welder or muffler shop cut the hole and install the new O2 bungs on your new mufflers (silencers) in the same place as on the OEM mufflers (silencers).
Your OEM muffler O2 sensors are part #32700127. I believe they are the smaller 12mm, heated O2 sensors Harley uses. The O2 sensor bungs you will need should have an M12 x 1.25mm thread pitch. If you buy the 18mm O2 sensor bungs, then you will need adapters to fit the 12mm O2 sensors into the bungs. That causes the O2 sensors to stick out of the muffler farther. It could affect the fitment, and many believe it will affect the O2 sensor readings..
Pull one of your O2 sensors out of the muffler (silencer) and confirm the threads size & pitch. I believe you will find them to be M12 x 1.25mm.
Whichever size they are, Harley has used both 18mm & 12mm O2 sensors over the years, it's better to be certain on the thread pitch before buying the new O2 sensor bungs.
Good luck with your mod...
Your OEM muffler O2 sensors are part #32700127. I believe they are the smaller 12mm, heated O2 sensors Harley uses. The O2 sensor bungs you will need should have an M12 x 1.25mm thread pitch. If you buy the 18mm O2 sensor bungs, then you will need adapters to fit the 12mm O2 sensors into the bungs. That causes the O2 sensors to stick out of the muffler farther. It could affect the fitment, and many believe it will affect the O2 sensor readings..
Pull one of your O2 sensors out of the muffler (silencer) and confirm the threads size & pitch. I believe you will find them to be M12 x 1.25mm.
Whichever size they are, Harley has used both 18mm & 12mm O2 sensors over the years, it's better to be certain on the thread pitch before buying the new O2 sensor bungs.
Good luck with your mod...
Hiya...thats great and appreciate your reply
Ive since been told that simply removing the sensor from the muffler and attatching it to the frame also work without throwing a warning light.
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Seasoned HDF Member
Joined: Sep 2008
Posts: 14,158
Likes: 11,249
From: San Diego, CA
I have never worked on, or owned a bike with the four O2 sensor set-up. I would be leery of just pulling it from the exhaust, and not somehow dealing with it in the tune. I would be afraid it would affect the AFR... But I have no direct experience with that.
If you want to remove the muffler O2 sensors, they appear to have rather short pigtails. I would just disconnect them from the harness, at their connectors. It would be one less thing in the way to worry about. You could plug the harness connectors, or just put a blob of dielectric grease in them, to preserve the contacts for possible future use.
They are shown in the HD parts pic below..
#23 Upper muffler O2 sensor #32700135
#24 Lower muffler O2 sensor #32700127
Last edited by hattitude; Apr 24, 2025 at 03:35 PM.
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