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[rayson56]

In the past with the Twin Cam CVOs a couple of the members here took it upon themselves to cut open the 2 into 1 into 2 header pipe at the catalytic converter to take pictures and share what they had found as well as pictures of the CVO touring muffler cores after removing them. I was hoping someone was willing to do this again with the M8 cat and cores to show how restrictive they are. Although the dealers are saying the M8 exhaust is much less restrictive than the TC I'd still like to see the comparison as I'm sure most of you would as well. So anyone have the stock stuff laying around that you're willing to cut up and take some good pictures of and post here? Side by side pics of the M8's and TC's would really be cool.

Thanks in advance!

[FLSTFI Dave]

With in the next two or three weeks I will be installing my Fullsac MX head pipe on my 18 CVO Road Glide.  I will be keeping the stock head pipe for warranty purposes if the need should arise. 

I really have not heard of people cutting the cats out of the M8 head pipes like they did with the twin cam.

[rayson56]

Just wanna see what the cat and cores look like in comparison Dave and see if the cat is as nasty and restrictive as this. :-)

[FLSTFI Dave]

When I take it off, I will take a picture if I can see the cat.  My guess is it is every bit as restrictive. 

[jcd520]

I just installed my fullsac stuff , tuned it today, and for grins I cut the cat section out of the stock headpipe to see what it looked like.
Much simpler than in the past, and I have de catted many of them. The cat section in the m8 is about 8 inches long , and is simply a section of 2 7/8 OD pipe with the catalytic converter in it. A simple replacement of that section of pipe is all thats needed, taking care to mark the alignment of the front and rear section so as to get it put back together straight..
Im gonna weld it all back together and have it for sale on here soon.
Ill post pictures tomorrow of the dissassembled stock pipe....

[jcd520]

Ok, heres a set of pictures of what I removed and did not put back on my 2018 cvo rg when installing all the fullsac stuff.

also a pic of the section with the cat after i cut it out and a picture of the cat material itself inside the 2.75 inch piece of pipe that holds it.

[jcd520]

after the cut

[jcd520]

close up of the cat

[jcd520]

a look inside at the cat

[jcd520]

You can see through it if you hold it up to the light , but it is very restrictive.
I am going to obtain a piece of muffler tubing (2 7/8 ) OD and weld it back together and see if someone wants to use it instead of buying a fullsac MX pipe. Im sure steve has dyno info on the difference between his and doing what Im about to do.
By the way------after riding mine last night with the muffler cores, tech mat kit, MX Pipe , I cant' begin to tell you all how good it runs and how glad I am I bought and modified this bike. Huge improvement over my 2012!!!!!

[jcd520]

So now here is the pic of the stock headpipe with no catalytic converter.

[rayson56]

Well that certainly satisfies my curiosity on the head pipe. Both dealers in my area have been saying what huge differences Harley made with the flow of the M8 factory exhaust. Again what they say and what we see here are 2 different things at least internally.
Great job JCD! Your pics and comments pretty well cover everything. How about a couple of pics of how restrictive the muffler cores are?

There was never any doubt in my mind about doing another Fullsac upgrade on my new bike, I'm just waiting for Santa to get here!

Thanks again for taking the time and effort to share this information.

Kelly

[jcd520]

It just so happens I dissected the baffles as well just to see what was inside. They are pretty different than the replacement fullsac cores for sure. Heres a pic of them cut apart. You can see the little bullet piece that stick into the baffle core ------it has some holes but the end is pinched shut--------Wondered what it would do to use the decatted headpipe , weld the baffles back together without the restricted piece and dyno tune the bike. It would have to be better than stock , but again , after several bikes with the fullsac stuff , I personally wouldn't try it unless I was really on a budget and wanting to save the money on the fullsac mx pipe.

[J.D.]

Couldn't you get most/all of the cat material out with something like a hole saw without cutting the header apart and rewelding?

[ultrarider123]

It just so happens I dissected the baffles as well just to see what was inside. They are pretty different than the replacement fullsac cores for sure. Heres a pic of them cut apart. You can see the little bullet piece that stick into the baffle core ------it has some holes but the end is pinched shut--------Wondered what it would do to use the decatted headpipe , weld the baffles back together without the restricted piece and dyno tune the bike. It would have to be better than stock , but again , after several bikes with the fullsac stuff , I personally wouldn't try it unless I was really on a budget and wanting to save the money on the fullsac mx pipe.

Worked great for me on my '12 and '15 (although with the FP3 instead of the dyno on my '15).  Removed and replaced the stock header with a de-catted one on several bikes including my own.  Removed the "plug" on quite a few bikes including my own.  I like the sound and it's fairly simple once you do the first one.

Fullsac is the way to go for sure but it's fun to tinker for much less money...I've enjoyed it anyway....