De-Catted 2011 Road Glide Ultra
Road Captain
Joined: Nov 2006
Posts: 610
Likes: 1
From: Oregon Ohio
If the cat is already gutted, its not that expensive to weld in some 18mm bungs. U can go cheaper on a tuner, I went with thundermax for the simplicity of not needing to dyno now or in the future if I do cams and headwork. The t-max nay sayers will say u can't adjust the timing, but low and behold I can on mine. I have paid for sert and powercommander and dyno time on two other bikes and the price for one of those bikes= t-max. So basicly it was my preference to go t-max this time around.
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Joined: Sep 2010
Posts: 94
Likes: 0
From: Merritt Island FL
If the cat is already gutted, its not that expensive to weld in some 18mm bungs. U can go cheaper on a tuner, I went with thundermax for the simplicity of not needing to dyno now or in the future if I do cams and headwork. The t-max nay sayers will say u can't adjust the timing, but low and behold I can on mine. I have paid for sert and powercommander and dyno time on two other bikes and the price for one of those bikes= t-max. So basicly it was my preference to go t-max this time around.
Thank you,
Tim
Road Captain
Joined: Nov 2006
Posts: 610
Likes: 1
From: Oregon Ohio
They will aide in an autotune type of tuner, such as tmax or pcv autotune. Otherwise they are not necessary. The autotune type use 18mm wideband sensors.
Cruiser
Joined: Feb 2010
Posts: 190
Likes: 2
From: Central MA
It sounds like to OP has an exhaust leak at the header flange. He should be running leaner with the cat removed, not richer. Introducing air into the exhaust stream from a leak is going to make the O2 sensors show a false lean condition. The ECM is going to add back too much fuel in an attempt to compensate to bring the bike back to the target AFR. However, this is a false reading due to the air leak.
It is possible it could be the O2 crosstalk issue mentioned but check the obvious possible causes first. If it does turn out to be crosstalk you could try relocating the bung that's in the collector to the pipe.
Make sure you put the O2 sensors in the right place - gray for the front and black for the rear. And get that tuner since you're going be running lean once you fix the issue.
It is possible it could be the O2 crosstalk issue mentioned but check the obvious possible causes first. If it does turn out to be crosstalk you could try relocating the bung that's in the collector to the pipe.
Make sure you put the O2 sensors in the right place - gray for the front and black for the rear. And get that tuner since you're going be running lean once you fix the issue.
Last edited by HDThunder; Apr 25, 2011 at 01:12 PM.
Road Warrior
Joined: Feb 2010
Posts: 1,534
Likes: 10
It sounds like to OP has an exhaust leak at the header flange. He should be running leaner with the cat removed, not richer. Introducing air into the exhaust stream from a leak is going to make the O2 sensors show a false lean condition. The ECM is going to add back too much fuel in an attempt to compensate to bring the bike back to the target AFR. However, this is a false reading due to the air leak.
It is possible it could be the O2 crosstalk issue mentioned but check the obvious possible causes first. If it does turn out to be crosstalk you could try relocating the bung that's in the collector to the pipe.
Make sure you put the O2 sensors in the right place - gray for the front and black for the rear. And get that tuner since you're going be running lean once you fix the issue.
It is possible it could be the O2 crosstalk issue mentioned but check the obvious possible causes first. If it does turn out to be crosstalk you could try relocating the bung that's in the collector to the pipe.
Make sure you put the O2 sensors in the right place - gray for the front and black for the rear. And get that tuner since you're going be running lean once you fix the issue.
Would there be any advantage to using the 18mm bungs, as opposed to the stock 12mm bungs?
Thanks
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Joined: Sep 2010
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From: Merritt Island FL
-Tim
Seasoned HDF Member
Joined: Feb 2007
Posts: 10,602
Likes: 721
From: Bellevue, NE
Can't speak for everyone, but my bike runs BETTER with the cat removed. I have stock A/C, Wild Pig muffs (with 1 3/4 inch baffles), no tuner. Granted, I only have a few hundred miles on since gutting it but so far I'm glad I did.
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Joined: Oct 2007
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not on a 2010 or 2011 unless you have a tuning device that uses wideband sensors that require the 18mm. On 10's and 11's the 02 senors are heated and will not last long if you put them up where the 18mm bungs are.
