**Decatting and modifying stock M8 header**

[NGOT8R]

I acquired a stock header from my buddy in exchange for installing a decatted header and mufflers on his 2017 RGS. My plan was to modify the header to my liking. So far, I have cut out a section from each primary tube and will be replacing those sections with 304 stainless steel and an 18mm o2 sensor bung in each. I purchased a chain style exhaust pipe cutter and cut the shell on the catalytic converter. I then removed the cat (for off-road use only), by drilling holes and using a pipe to knock the cat out. I still have to clean up a little residual cat material that remained stuck to the walls of the shell and bevel the two halves in preparation to be welded. Once I get all of my parts in hand, I will take everything to my buddy and have him Tig weld it together. Here are a few pics.

 

[NGOT8R]

Pic of the chain exhaust cutting tool that I used. It took about 250 revolutions around the pipe to make the cut, but as you can see, the cut is very clean.

 

[NGOT8R]

Man is the residual cat material extremely hard to remove from the walls of the cat shell! I tried using a wire wheel on the end of a drill and that didn't work as well as I had hoped it would. Does anyone know of an easy way to remove the material?

 

[18flhxs]

Gasket scraper or putty knife and a hammer and just chip away at it.definately time a consuming job,youll get it.

 

[NGOT8R]

Gasket scraper or putty knife and a hammer and just chip away at it.definately time a consuming job,youll get it.

Thanks 18flhxs. I'll give it a try. I don't see how anyone is getting all of the material out of the shell without cutting it in half to,gain better access. I've read a few threads in which people have claimed to get everything out by drilling and then scraping. It just seems impossible to me.

 

[NGOT8R]

Today I finished removing the residual cat material from the inner walls of the cat shell. Man is this stuff difficult to remove! You cannot scrape it off, you must carefully sand it down until it's smooth. I am happy with the results. Here are some comparison pics.

 

[MKA_5966]

Wonder what the chances are of this being an option? Just thinking about the accuracy of aligning and welding it all back together. Price seems reasonable enough.

https://www.ebay.com/itm/Modified-C...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

 

[NGOT8R]

Wonder what the chances are of this being an option? Just thinking about the accuracy of aligning and welding it all back together. Price seems reasonable enough.

https://www.ebay.com/itm/Modified-C...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

I saw that listing on eBay. It looks to me like they cut it at the seems and down the length of the cat shell too. I'm sure they marked the pipe with a sharpie like I did before making the cuts. Then they would just line up the marks, weld it back together and the alignment remains the same as stock. I say go for it. If you do, will you please post pics of the quality of the welded sections? Thanks

 

[NGOT8R]

Got the header welded back up with the new 18mm o2 sensor bungs installed. I hit the pipe with a scotch bright pad and stainless steel cleaner/polish afterwards, to make it look nice. You can see the difference compared to the crossover pipe, which I'll be doing as well. I think it turned out pretty nice. I'm even thinking of sending it out to Jet Hot to have it ceramic coated, but I'll decide on that part after I've had a chance to test fit it on the bike.

 

[NGOT8R]

A couple more.

 

[Schöni]

Good work.
Thx for sharing!!!