I finally decided to get rid of the cat on the stock header. I only had about an hour yesterday to work on it, so I got the exhaust disassembled and begin drilling out the cat with the spade bit. I'll finish up this afternoon.

Rather than buying a 16 inch long 1 inch spade bit, I bought a 12 inch extension and a standard length bit. They measured up lengthwise about the same. I wrapped the collector portion of the pipe in an old shirt and placed it in a vice. I bought a brand new corded DeWalt hammer drill as I didn't think my crappy cordless would have the nuts to make it through the endeavor. I'll have to take it back though - I'm pretty sure the bearings on it are already going bad even though it was only used for about 20 minutes.

I haven't finished getting all the material out yet, but so far, so good. I was surprised how well the spade bit (Irwin) held up, but I was also taking my time to make sure it didn't get too hot. And yes, it does clean it out well. I can still see some of the adhesive on the wall ID of the tube, but the material itself is gone. I'll try to take some pictures this afternoon as well.

For those trying, you can keep the dust down by sticking a shop vac into the crossover pipe connection on the header. I had zero issues with dust. Also, I would probably just buy the 16 inch bit rather than the standard bit with the extension. The bit with the extension is reasonably flexible and probably doesn't allow as much control as a 1-piece bit. And use a good drill with a side handle. It will kick and jerk as it chews through the material.

 

What size spade bite did you use?
Thanks

 

Take it to a muffler shop. Cut a rectangular opening about 2 inch by 3.5 inch and dig into it then re-weld. My muffler shop charged me 30Bucks for this and it was done right.

Very clean.

 

Let us know what you think after you get it installed. I have a pipe I got off of fleabay waiting on me when I get back from Afghanistan in Sept. I can't wait.

 

So before I had to stop the other day, I had about 80% of the material removed. I was able to finish up yesterday, and it only took another 10-15 minutes to removed the rest of the material. I wish I could have gotten a good picture - the material was completely removed except for some remaining adhesive. I took an old cable bike lock and threaded it through the exhaust entrance ends of the pipe to make sure there were no chunks remaining. I have a Streamlight LED flashlight I used to inspect the pipe so I could clearly see into the chamber.

I though maybe there was still material on the upper side of the collector (crossover pipe side) that I couldn't see, so I stuck a finger in the crossover exit side and looked through straight exit side. I could see my finger, and did a clean sweep with my finger to see if I could feel any left over material. Nothing. Being diligent about it, I still tried to use the bit to see if I could feel any more material along any of the walls of the pipe. Still nothing.

I also had my wife take a look to see if she could see any material that I didn't see. Should couldn't find anything either. I called it good, shook and vacuumed the pipe out one more time, and put everything back on.

The bike does sound a little different. It is louder, but not incredibly so. The tone is also deeper and more throaty. My wife stated this before I even asked her if it sounded different, and she had no idea it would sound any different. It's more noticeable through the gears than it is at idle.

As far as the heat, I can't say yet since I haven't had any extended seat time to tell. I probably would need the wife to confirm anyways, as it seems to affect her first before me. If she wore anything other than boots in the summer (tennis shoes, etc) she couldn't keep her foot on the board if we were stopped at a light because of the heat.

A few things based on my experience:

• If you have a shop vac, stick it in the crossover pipe exit end while you drill it out. I had zero dust issues.
• Use a 16" long by 1" spade bit, not a shorter bit with an extension. The extension does allow for more bit wobble. They should be around $10 at hardware stores. The bit I had used, Irwin, held up great.
• Use a drill with a forward handle. The drill will catch and rip the material, and it will kick the drill.
• Make sure the pipe is clear of any debris when you're finished drilling. Use a wire, coat hanger, etc to thread through the pipe. Also use a good flashlight so you can see clearly.
• I took probably a total of 30-45 minutes to drill it out, going slow to make sure material was being removed properly. Usual I would drill out for 20 seconds or so, then stop and inspect. It probably could be done faster, but I would opt to take the time to make sure its cleared out properly. It also allowed for the bit to cool to prevent it from bending.

I opted to drill over the "cut, gut, and weld" to maintain the integrity of the pipe. With an experienced welder it shouldn't be an issue, but drilling it out removes the risk of a bad weld from the equation all together and didn't take long to do. I don't think one way is necessarily better than the other if executed properly.

For those that doubt the material can be completely removed this way, I'd say personally try it before stating it can't be done. I wasn't sure it would work either and was planning on taking it to a shop if I couldn't get the material out. It worked great.

 

Good write up.

 

Thanks for the detailed write-up!

Planning on doing this myself and your info really helps.

 

been saying this all along.

 

The thing is your finger isn't long enough to even reach the CAT material. So if there is any left, on the crossover side, which I'm sure there is, you wouldn't be able to see it or feel it. This issue has been beat to death. There is physically no way, because of the angle, that you can get all the material out with just a drill bit. If you have ever taken one apart. which I have, you can plainly see this. Did you get most of it out? Probably so. But for me that wasn't good enough. I wanted it all out so I cut mine in half, removed all the material and the glue from hell that holds this stuff in there, and had it welded back together. For me there is no doubt that I got it all out. Does it matter if it's all out or not including the nasty glue? Who knows. But I wanted to make sure it was clean.

 

The finger sweep was to look for blockage on that side of the port and to verify I could see all surfaces of the pipe ID that had the cat material. I have fairly large hands, and I could feel most of the wall I couldn't see. The cable bike lock I used was long enough to thread the entire length of the pipe from front cylinder inlet to the straight outlet. It's a large cable - about 1" diameter - and rigid enough ride the wall of the pipe. I pushed cable along the entire wall and couldn't find anything that would suggest remaining material. As far as the adhesive, it could be cleaned out if it makes you sleep better at night, but it's not going to make a difference if it's removed or not.

Again, if you haven't done it, then you can only speculate how effective it really is.

Edit: I found the original thread showing the cutting a window that has a good picture of the cat material location. Based on the picture I have no doubt all the material is removed.
https://www.hdforums.com/forum/touri...with-pics.html