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So what are the chances that gutting the cat causes a loss of back pressure and I loose bottom end? ( Im not real concerned with top end, I only see speeds above 95 for very short spurts on very limited straightaways here in upstate NY. )
Zero, if you have an FP3, just leave it in self-tune mode and forget about it. That way it will always be correct, whatever is going on around you.
People get hung up on maps and locking in a self-tune map.
Zero, if you have an FP3, just leave it in self-tune mode and forget about it. That way it will always be correct, whatever is going on around you.
People get hung up on maps and locking in a self-tune map.
I'd question that because when in "self tune" mode you usually have a much bigger area (lean) in closed loop than needed.
I have a FP3. I have talked to V&H and leaving the tuner in the auto-tune mode doesn't work. It is ONLY reading and NOT making any adjustments. It has to be flashed to the ECM to save the changes.
I gutted the cat from my new to me 2022 RGL about one week after I brought her home. It bothered me that it was there, big brother and all of that and did not want to deal with the possible heat issues. It did make the bike a little louder but I doubt any noticeable performance gains. Bike came with Rhinehart muffler and HD free flowing air cleaner, so after the Cat was gone I had a tuner put in and a run on the Dyno. Ran a little better after, my guy tells me she really wants a cam, but I have other things that need my $$$$ so that is all she is getting for now.
I left the head pipe on the bike, ran a long drill bit then small hole saw down into the pipe until the thing came loose and was pulled out with a hooked piece of steel. Then I sucked out all the remaining debris, whatever was left get blown out when the bike was started. Helped my buddy do the same thing on his 2021 RGS, so my second go at it only took an hour or less. I probably spent more time getting the f-in muffler off.
Personally, I feel the de-catting in modern machines is over-hyped relative to performance. More volume and reduced heat for sure, but de-catting doesn't suddenly open-up a whole lot of power, and more likely may introduce a performance issue and a rabbit hole. Here's my personal experience for what it's worth:
About five months into my new 2018 SG I had the H-D SE High-flow exhaust installed. The passenger-felt heat under the right side was gone (the SE HF exhaust has the cats in the mufflers) and the bike ran well. Over time I came to dislike the aesthetics of the pipe, especially the way the heat shields went together, and the pipe was not aging well.
In late 2020 I swapped the pipe for V&H Power Duals w/ Torquer 450s. Absolutely loved the look and hated everything else. The bike was now way too loud for me, and more importantly, my low-end was gone (<- free-flowing, no cat). It was like the power-band moved up 1,500RPMS which was outside my normal operating range. Smell of the exhaust now very prominent.
A little over a month and about 500 miles later I had enough of this nonsense and installed DK Thunder Torque Inserts. Totally solved my low-end power issues. Bike quieted down a bit, but still a bit loud. Still not perfect for me...
In late 2021 I swapped the mufflers for Rinehart MotoPro 450s w/ Catalyst (had to buy their complete exhaust system; installed the mufflers and sold the Rinehart head-pipe). Got the tone I wanted and the exhaust was cleaned-up a bit. Mufflers are still pretty free-flowing so I popped in a set of TTIs and voila - perfection to me. Power exactly where I want it.
I have not touched the exhaust since then and don't plan to. Just sharing my experience. YMMV.
Last edited by Old Sport; Oct 28, 2025 at 09:24 AM.
I gutted the cat from my new to me 2022 RGL about one week after I brought her home. It bothered me that it was there, big brother and all of that and did not want to deal with the possible heat issues. It did make the bike a little louder but I doubt any noticeable performance gains. Bike came with Rhinehart muffler and HD free flowing air cleaner, so after the Cat was gone I had a tuner put in and a run on the Dyno. Ran a little better after, my guy tells me she really wants a cam, but I have other things that need my $$$$ so that is all she is getting for now.
@Architect I left the head pipe on the bike, ran a long drill bit then small hole saw down into the pipe until the thing came loose and was pulled out with a hooked piece of steel. Then I sucked out all the remaining debris, whatever was left get blown out when the bike was started. Helped my buddy do the same thing on his 2021 RGS, so my second go at it only took an hour or less. I probably spent more time getting the f-in muffler off.
So, once you got a good amount of the Cat out, the rest just pulled out without much of a fight? And was there any small chunks of Cat still stuck to the inside of the pipe? And if so, did you just use a wire wheel to clean it up? I'm not going after any power increase, just want the excess heat to go away......
2017 Road King. K&N air, V&H slip ons. I installed the Dynajet PV4 last week, did about 8 tuning sessions and my impressions has just been 'meh'. 20% of the folks here seem to say that they noticed an improvement with this combo, the other 80% say 'you need a cam to feel any difference'. I ride the bike hard, Im heavy on the throttle, I just cant bring myself to pay 3-4 grand for a cam job. I used to build car engines for fun, but that was years ago, so I know my way around a wrench, but I dont know if Im willing to undertake a cam job
by myself.
Cam job is easy if you know your way around a tool box. Just heat the cuff bolts till they soften the red locktight. Fuel Moto will provide correct pv4 tune file that is very close, just a few autotunes and you'll be good. Probably about $750 in parts. Cam, lifters, adj pushrods, gaskets. You've already got the tuner. You may need to borrow a inner cam bearing remover/installer, or get one off Amazon for $60.
So what are the chances that gutting the cat causes a loss of back pressure and I loose bottom end? ( Im not real concerned with top end, I only see speeds above 95 for very short spurts on very limited straightaways here in upstate NY. )
Look at my dyno chart above in this thread. No loss of low end with gutted cat.
Zero, if you have an FP3, just leave it in self-tune mode and forget about it. That way it will always be correct, whatever is going on around you.
People get hung up on maps and locking in a self-tune map.
Not good advice. Autotune mode sets certain parameters for gathering data, not for performance.
Over-hyped...
