Another Way to "Skin the CAT"

I wanted to get rid of the CAT's and considered getting a set of TOR's. Couldn't actually find any for less than $500 with shipping that weren't *****ed up. I also didn't want to increase the noise, so I decided to launch into a project of removing the CAT's from the stock 2013 roadster pipes.
I wasn't really sure what I would find so I took pictures in case anyone else might want to try this and/or find a better way to "skin the cat"

First, I opened up the can at the inlet end with a 1/16 ziss wheel so there would be a way to weld it back together without cosmetic issues:




So that's just the can, or outer shell. There's another pipe, much thicker, and I used a Sawzall bi-metal blade to reach through that slit and cut that pipe:



The inner canister of this thing is really surprisingly thick and is why each of these weighs 17lbs.



Before you cut all the way through, make some marks across the slit to index the two pieces so when you weld it all back together the angles are correct to fit the crossover unit.

So at this point I had no idea how deep the CAT would be or how to get it out? It isn't at all like the ceramic ones that just crumble. This stuff is really really tenacious tuff stuff. Some kind of super metal foil. All I could find on the internet was that it is referred to as a high flow catalyst?




I tried a big 3/4 inch drill bit to start but it doesn't work. It just folds over the metal at the tip of the bit and kind of makes a dent so the cutting edge can't get under the material to take a bite and bore the hole?


You can sort of see the dent it made. So I got a smaller, longer 1/4 inch bit and just had at it poking holes. Once you get a hole out of the center then you can kind of grab the material with needle nose pliers and roll it towards the open center as you would to open a sardine can.


So it turns out the catalyst material is about 4 inches diameter and 4 inches deep. It took me 5 minutes to cut open the canister and nearly 2 hours to get the catalyst out. The next one I did, I burned a hole in the center with a cutting torch and it was much quicker but still not a cake walk to unravel the metal foil.


So this is ready to go back together. You want to take a dremel tool with a stone around the inside surfaces where you will be welding so that there's less contamination in your weld. I used TIG and stainless steel rod and it welded pretty nicely. Here's a drawing of what I think is roughly the design of these mufflers:






Index marks to get it back together and aligned properly


I reached the limit for photo uploading so I will post the rest as "Skin the CAT" continued. Hope these help or inspire others to give it a try. Even if you can't weld, you can do everything up to this point and then take it to someone who can weld it very easily.

Not sure of the best way to continue the thread but here's the muffler back together and ready to install

Next week I will set up a way to record the bike running with the stock mufflers and then In the exact same setting with these "skinned" CAT's. I will also try to detect if there's any appreciable performance increase before changing the stock tune.

Well done liked the step by step photos.should be a throatier W/out the cats in them.

My hat off to you my good Sir that is one excellent post not sure how many will follow you(due to lack of skill) good looking welds and should sound pretty good, wonder if you will have to retune the bike?
Nice drawing also sadly stick figures are my limit.

Excellent, very well documented.

Nice job..! I've had my day with the sawzalls,i finished a base ball back stop and tried those Diablo blades,you still have to take your time with them.

TRIIICK said:

Nice job..! I've had my day with the sawzalls,i finished a base ball back stop and tried those Diablo blades,you still have to take your time with them.

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I just used a standard Milwaukee bi-metal blade and it went through it like butter? I mean maybe 1 minute, max. It's a thick wall pipe canister and heavy but I think the metal composition is pretty soft. The real time consuming part of this is just chewing or gnawing through the catalyst.

Very well done. I just completed the same kind of project, with the exception of I completely gutted the inside of the stock pipes and installed 2"x4" cones. I tried just the cat as you have done and wanted more sound. 2nd time got lots of sound, which I'm very happy with. Also after dyno got 132 hp and 155 tq. Very good pics and write up.

Wannbe said:

Very well done. I just completed the same kind of project, with the exception of I completely gutted the inside of the stock pipes and installed 2"x4" cones. I tried just the cat as you have done and wanted more sound. 2nd time got lots of sound, which I'm very happy with. Also after dyno got 132 hp and 155 tq. Very good pics and write up.

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Thanks, ya I saw your post of your project and it actually enticed me to do this. I might be the only one trying not to get any more sound (volume wise) as I like to go on long cruises. I wouldn't mind a different note though? I'm not sure if there will be any difference at all but we'll see. I was also hoping to reduce weight too, but didn't realize it's all in the canister not the CAT. Thanks for your post. It really helped, and glad you like your sound. Did you change from the stock tune to get the 132HP?