need some truth: I was thinking about how to get rid of the Cat without voiding the warranty so I thought I would put SE head pipes on with aftermarket slip-ons. My local HD shop maintenance guy said it wouldn't work, the SE heads have different "angles" that will only fit SE mufflers. This just seems wrong and I wanted to verify. Is there any truth to what he said?(aside from the angel of getting more $ for the SE mufflers)

 

that is correct.. as far as HD parts are concerned, you have two options... The orginal stock head pipe which contains the cat, and mated to a set of SE street cannon mufflers.. (not much improvement in sound or performance)

or SE headpipe which does not contain a cat BUT can only be mated to a different set of SE street cannon mufflers that have the cat in them. That's why they sell them as a kit.

The key here is that HD will include the cat one way or another for EPA compliance. Otherwise everyone would just get the SE catless head pipe and throw on some aftermarket mufflers. I honestly do not know if there is any difference in the two kits as far as performance or sound is concerned. In my case, which may or may not be the same with you, I was able to purchase V&H power duals and mufflers from HD and was told it would not void my warranty as long as it came, and was installed from them, and I only used the SE tuner. So far they have kept their word.

 

Thanks for the feedback. That is pretty much what he told me as well. What is the different angle in the head pipe and where is it?

 

It’s actually different diameter pipes where the mufflers and pipe meet. My guess is someone could probably expand or shrink the pipe where necessary to make it work...but the question would be why? The head pipe by itself would not be EPA approved without the mufflers which have the stamp on them. So at that point that’s a lot of cheddar for a pipe that won’t be compliant anyway.

As for performance I had the system on my 2015 and they ran good and were pretty quiet. I noticed zero difference from running fM 2-1-2 with jackpot mufflers in performance. But to my ears sounded better (I don’t like loud).

 

I'll get hammered here but, why get ride of the cat? These M8s run better and stronger than any other Harley I've been on.
Leave the stock head pipe on, do slip on mufflers and stage 2 with a torque cam. I promise you will be in love with it.

 

There are some having problems with heat from the cat. Others believe it robs performance. A few that like the smell.

Only reason I would remove it is if wife is complaining about the heat. I tried the coolflow fan and it solved her heat problem so cat stayed.

 

And if you don't care about warranty or have already lost it like I have. Decat or new headpipe make the ride cooler by a large margin. Bike sounds better.

I already have a solid Stage II bike with slips, se tq cam, a/c, se tuner or fp3. Knocked the cat out heat is gone. Put the se tuner back on. Street tuned it all week and built a new map. Turned out to be pretty much Obummer and his epa crap. Crap pretty much like everything else that mother ****er has done. Saved the Obummer **** head epa map and put the fp3 back on. Hello a new bike was born. Obummer should have been shot at golf practice the pos.

Just went out and broke one of my personnel riding rules. And I'm thankful it went ok. I just had to know. I rode the bike for a hour wearing shorts, sleeveless-t and sneakers. It's a 102f here and the sun is shining like a evil sob. The right side of the bike is drastically cooler than the left side. I was blown away. Intake air temp has dropped 20 to 40 degrees depending on if your setting traffic idling or blasting down the road.

Now with the warranty gone I can continue on with getting rid of the Obummer/EPA/And **** head Cali Crap that the HD CEO bent over and took.

 

Get a normal M8 header with out cutting the pipe remove Cat from the end . It is easy to get to not like the pre M8 one. Install it save yours with the cat in it if you need it..

 

If I'm reading your reply correctly, the SE pipes are different diameter than stock pipes? I'm looking for sound and trying to stay under warranty. I couldn't give a rip about EPA compliant. I'd also like to cut down on the heat coming off the heads, it's been a brutal summer for that.

Back to the question, what is the difference in diameter of the the stock v. SE heads? And does this mean if I wanted to put SE mufflers on my stock system I couldn't because of the difference in diameter as well?

Thanks in advance for your help!!

 

On the stock the left side is bigger than the right and your standard slipons are made for that size. The SE system they used a proprietary size on both sides so that standard slipons could not be used easily. This is to comply with the EPA so that it can’t be tampered with or defeated for emissions.

If you don’t care about epa then just get an aftermarket head pipe that will work with all standard slipons available. There is zero benefit to the SE system unless you like the sound of the SE mufflers that can only be used with it.

Disclaimer: I do not know exact diameter of the pipes either stock or SE. I just know that slipons do not work with the SE headpipes.