catalytic converter question

Hellkitty · 02-26-2018, 09:35 PM

Hi, this is a picture of an exhaust header off my Hellcat. The bulge in the middle is a catalytic converter. I imagine it is packed with some type of material that restricts the flow. Is there any way I can remove the material without cutting my pipe?

roundhouse · 02-26-2018, 10:31 PM

I do not think so. Might be easiest to cut the cat out and put in a piece of straight pipe.

letsride · 02-27-2018, 01:16 AM

JerryHawk has a thread about how to do it. Search his posts. I believe he made a three sided cut, folded the flap back, removed all the cat guts and then folded the flap back down and welded it up. Let me see if I can find the thread.

letsride · 02-27-2018, 01:21 AM

Nevermind, Jerry cut the cat in two. But I remember someone on here did it the way I described. Here is Jerry's thread. I know this isn't what you want but its probably the only way to gut the Cat.
http://www.chinariders.net/showthread.php?t=17913

Hellkitty · 02-27-2018, 02:12 AM

Quote:

Originally Posted by letsride

Nevermind, Jerry cut the cat in two. But I remember someone on here did it the way I described. Here is Jerry's thread. I know this isn't what you want but its probably the only way to gut the Cat.
http://www.chinariders.net/showthread.php?t=17913

Thanks for the link! Based on what I read in Jerry's thread it's not easily removed. looks like I'll have to find someone to cut it out and and weld a piece of pipe on it.

**JerryHawk250** · 02-27-2018, 08:01 AM

Quote:

Originally Posted by Hellkitty

Thanks for the link! Based on what I read in Jerry's thread it's not easily removed. looks like I'll have to find someone to cut it out and and weld a piece of pipe on it.

That would be the best solution. I kept the cat housing for two reasons. First being i wanted to keep the mounting points for the heat shield. Second was i didn't have a piece of pipe laying around that was the right size. You go by one of the local muffler shops and have them cut and weld a piece of pipe on there for you or just piece of exhaust pipe and use muffler clamps.

Weldangrind · 02-27-2018, 10:58 AM

If you cut 3/4 of the way around the pipe, you won't lose the overall length or configuration of the stock exhaust. If you have someone cut the offending section out and replace it with a new piece of tube, it might end up being the wrong length, the bolt holes might not line up or the mid-pipe might not meet the muffler.

It's much better to take the time to cut 3/4 of the bulge out and remove the cat yourself. That way, you can hand the whole deal to a welder and simply instruct him to weld the window back in. It's also much easier for him that way and is likely to cost you less. If you brought it to me like that, I'd do it for free.

**JerryHawk250** · 02-27-2018, 11:35 AM

Quote:

Originally Posted by Weldangrind

If you cut 3/4 of the way around the pipe, you won't lose the overall length or configuration of the stock exhaust. If you have someone cut the offending section out and replace it with a new piece of tube, it might end up being the wrong length, the bolt holes might not line up or the mid-pipe might not meet the muffler.

It's much better to take the time to cut 3/4 of the bulge out and remove the cat yourself. That way, you can hand the whole deal to a welder and simply instruct him to weld the window back in. It's also much easier for him that way and is likely to cost you less. If you brought it to me like that, I'd do it for free.

I used a center punch to make reference marks so I could line everything back up before welding.

Hellkitty · 03-01-2018, 02:07 AM

Thank you guys for all the great advice! Reading various articles on the net, there seems to be a lot of debate as to whether removing the cat is all that beneficial, as far as gaining more power. One thing that appears to be clear is that it will make your exhaust louder if you remove it. I installed an aftermarket
performance muffler and I like the way it sounds, not that loud with the db killer in, and I want to keep it that way, so I decided just to leave it be for now.

Thanks

Sir kayakalot · 03-04-2018, 05:38 PM

I cut three sides and peeled it back and dug out the mess then folded it back over and welded it. The toughest weld job I've ever done. That metal is terrible to work with. I posted pics in my build thread (probably 50 pages back in the archive by now). As far as performance benefits..... by far the best thing I ever did to my Hawk. Coupled with re-jetting the carb and modifying the air box it really made a big difference. The catalytic converter doesn't come out easy tho

02-27-2018, 01:16 AM	#3
letsride Join Date: Oct 2013 Location: Leesville SC Posts: 835	JerryHawk has a thread about how to do it. Search his posts. I believe he made a three sided cut, folded the flap back, removed all the cat guts and then folded the flap back down and welded it up. Let me see if I can find the thread. __________________ My Stable- 2022 Lifan KPX250 , 2023 Royal Enfield Himalayan, 1992 Honda GL1500 Goldwing, SSR 70 Auto, Kymco Mongoose 90, Honda Four Trax 300
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02-27-2018, 01:21 AM	#4
letsride Join Date: Oct 2013 Location: Leesville SC Posts: 835	Nevermind, Jerry cut the cat in two. But I remember someone on here did it the way I described. Here is Jerry's thread. I know this isn't what you want but its probably the only way to gut the Cat. http://www.chinariders.net/showthread.php?t=17913 __________________ My Stable- 2022 Lifan KPX250 , 2023 Royal Enfield Himalayan, 1992 Honda GL1500 Goldwing, SSR 70 Auto, Kymco Mongoose 90, Honda Four Trax 300
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02-27-2018, 10:58 AM	#7
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	If you cut 3/4 of the way around the pipe, you won't lose the overall length or configuration of the stock exhaust. If you have someone cut the offending section out and replace it with a new piece of tube, it might end up being the wrong length, the bolt holes might not line up or the mid-pipe might not meet the muffler. It's much better to take the time to cut 3/4 of the bulge out and remove the cat yourself. That way, you can hand the whole deal to a welder and simply instruct him to weld the window back in. It's also much easier for him that way and is likely to cost you less. If you brought it to me like that, I'd do it for free. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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03-04-2018, 05:38 PM	#10
Sir kayakalot Join Date: Dec 2016 Posts: 269	I cut three sides and peeled it back and dug out the mess then folded it back over and welded it. The toughest weld job I've ever done. That metal is terrible to work with. I posted pics in my build thread (probably 50 pages back in the archive by now). As far as performance benefits..... by far the best thing I ever did to my Hawk. Coupled with re-jetting the carb and modifying the air box it really made a big difference. The catalytic converter doesn't come out easy tho __________________ Hawk 250 Mikuni carb 115 main. De-catted pipe. Air box mod. 15/42 sprockets. Digital instrument cluster, FMF end cap on muffler, handlebar toolbag, Custom foot pegs
	1

02-26-2018, 10:31 PM	#2
roundhouse Join Date: Sep 2017 Location: N Texas Posts: 706	I do not think so. Might be easiest to cut the cat out and put in a piece of straight pipe.
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03-01-2018, 02:07 AM	#9
Hellkitty Join Date: Dec 2017 Posts: 216	Thank you guys for all the great advice! Reading various articles on the net, there seems to be a lot of debate as to whether removing the cat is all that beneficial, as far as gaining more power. One thing that appears to be clear is that it will make your exhaust louder if you remove it. I installed an aftermarket performance muffler and I like the way it sounds, not that loud with the db killer in, and I want to keep it that way, so I decided just to leave it be for now. Thanks
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