Exhaust Crossover Plug size
Stellar HDF Member
Joined: Sep 2009
Posts: 2,114
Likes: 666
There is only a performance loss from eliminating the extra exhaust flow from the additional, left side pipe/muffler.
You would be doing this mod because you like the one-sided appearance NOT for performance.
The MOCO did that on a RoadGlide model some years ago. By replacing the single-sided exhaust with the normal FLH dual exhaust system, the bikes make 3-5 hp on top because of the additional flow.
Bob
You would be doing this mod because you like the one-sided appearance NOT for performance.
The MOCO did that on a RoadGlide model some years ago. By replacing the single-sided exhaust with the normal FLH dual exhaust system, the bikes make 3-5 hp on top because of the additional flow.
Bob
Last edited by FLTRI17; Nov 20, 2024 at 03:49 PM.
Road Captain
Joined: Sep 2007
Posts: 602
Likes: 51
From: central MN
There is only a performance loss from eliminating the extra exhaust flow from the additional, left side pipe/muffler.
You would be doing this mod because you like the one-sided appearance NOT for performance.
The MOCO did that on a RoadGlide model some years ago. By replacing the single-sided exhaust with the normal FLH dual exhaust system, the bikes make 3-5 hp on top because of the additional flow.
Bob
You would be doing this mod because you like the one-sided appearance NOT for performance.
The MOCO did that on a RoadGlide model some years ago. By replacing the single-sided exhaust with the normal FLH dual exhaust system, the bikes make 3-5 hp on top because of the additional flow.
Bob
Tourer
Joined: Oct 2010
Posts: 406
Likes: 241
From: NW MO
Big difference between choking it all down to 1.75 in 2009ish vs the 2.5 RH outlet on an M8. My personal experience is blocking off the left side works better than 2 pipes on a 2020 RG with a 114 S&S 475 and KW louvered baffle muffler on a stock decatted pipe. Change cam, head pipe or muffler core size and it might not.
Last edited by harpwrench; Nov 20, 2024 at 07:30 PM.
Stellar HDF Member
Joined: Dec 2009
Posts: 2,561
Likes: 280
From: North Cental Iowa
I've run this set-up since day 2 on my 17 RG using the Khrome Werks muffler, both KW & Bassani have this option complete with the plug for the crossover. KW tested it, as they do with all of their exhausts, and showed a gain of 3-4 on tq and 1-2 on hp on a stock motor. I continued to use it when I went to stage 2 further modding it by de-catting it and fully cutting out the crossover pipe and plating over the hole, essentially turning it into a 2-1 headpipe, granted with shorter primary runners. I'm still running it as a stage 3 114 now with a Star 30/30, I might be giving up just a little, but it sounds great and performs well and at $500 I'm happy.
Stellar HDF Member
Joined: Sep 2009
Posts: 2,114
Likes: 666
My opinion is based on my results as measured by the 250i dyno in our facility.
If you are convinced removing the additional flow from the system actually makes power, well we all have opinions some are based on seat of the pants and some are based on actual measurement using a machine.
To each his own👍🏼
Bob
If you are convinced removing the additional flow from the system actually makes power, well we all have opinions some are based on seat of the pants and some are based on actual measurement using a machine.
To each his own👍🏼
Bob
Last edited by FLTRI17; Nov 21, 2024 at 04:23 PM.
Road Master
Joined: May 2008
Posts: 1,232
Likes: 428
From: Northern NY
I've run this set-up since day 2 on my 17 RG using the Khrome Werks muffler, both KW & Bassani have this option complete with the plug for the crossover. KW tested it, as they do with all of their exhausts, and showed a gain of 3-4 on tq and 1-2 on hp on a stock motor. I continued to use it when I went to stage 2 further modding it by de-catting it and fully cutting out the crossover pipe and plating over the hole, essentially turning it into a 2-1 headpipe, granted with shorter primary runners. I'm still running it as a stage 3 114 now with a Star 30/30, I might be giving up just a little, but it sounds great and performs well and at $500 I'm happy.
Thanks
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Stellar HDF Member
Joined: Dec 2009
Posts: 2,561
Likes: 280
From: North Cental Iowa
No pics, it looks just like one of the aftermarket headers that use the stock heatshields with a 4.5 muffler, because that's what it is. I just cut the crossover out because it sticks out into the headpipe about 1/2 inch, some people ground off the protruding pipe even when using it as a 2into2 setup so the right side pipe was a clean shot straight thru. As harpwrench stated the M8 stock header has the same outlet size as all the other full 2-1 complete systems have, it's not like the 2-1 system the 2009s had. I did have to add the KW db reducer after decatting to gain back some tq, especially with the 475 cam. I think Bob's point was that if you used the stock muffler after plugging the crossover that you would lose exhaust flow.
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