Brozz catalytic converter removal

MOTOXtreme · 05-18-2017, 09:52 PM

Ok, this was WAY harder than I imagined it would be. Was hoping to make one cut and get it all out that way. Needless to say, that didn't work. You can see I tried my air hammer and it simply made a mess of it.

Ending up cutting it out on both sides and welding everything back up. Weld looks hideous but it works. This was mainly a test to see if there was any performance gain. I believe there was, but maybe I'm just wanting there to be???

I now occasionally get some light pop pop popping when I decelerate and I think I may need to go up a jet size. I need to inspect the plug and see how its running.

dpl096 · 05-18-2017, 10:03 PM

I don't recall who but someone else removed their cat too but the cut a panel out on the engine side of the body and then dug the material out. Welded the panel back on and from the outside no one can tell it was modified. Seems to me he was from Alabama and ended up selling the Hawk over registration/title issues with the state.

BigWeld · 05-18-2017, 10:25 PM

Hey! I removed my Brozz's cat today, too!

MOTOXtreme · 05-18-2017, 10:27 PM

Quote:

Originally Posted by BigWeld

Hey! I removed my Brozz's cat today, too!

Cool. Figured it darn sure couldn't hurt. Let me know your thoughts after you put some miles on it with it removed.

MOTOXtreme · 05-18-2017, 10:28 PM

Quote:

Originally Posted by dpl096

I don't recall who but someone else removed their cat too but the cut a panel out on the engine side of the body and then dug the material out. Welded the panel back on and from the outside no one can tell it was modified. Seems to me he was from Alabama and ended up selling the Hawk over registration/title issues with the state.

You couldn't pay me to dig this stuff out

. I tried and it was not fun.

Weldangrind · 05-19-2017, 02:09 AM

It'll most likely need a couple of sizes bigger on the main jet after a cat-ectomy.

pete · 05-19-2017, 02:35 AM

since you had the pipe open why did you not
turn the cat chamber into a power bomb ?

..

old kid · 05-19-2017, 07:00 AM

you can do this in one cut if you cut the cat. converter in the center and remove the two halves, i punched a 1/2" drill thru them and pulled the rest out with vise grips. I would also suggest installing the pipe back on the bike and tack welding the two halved back together. make sure they are where they need to be.

also some black heat wrap around the header pipe will cover it up if your worried about how it looks.

MOTOXtreme · 05-19-2017, 07:03 AM

Quote:

Originally Posted by pete

since you had the pipe open why did you not
turn the cat chamber into a power bomb ?

..

This was just a test really to see if there was anything gained from it's removal. I did get to see how heavy the stock exhaust is. So I'm probably ordering the aluminum exhaust soon.

**JerryHawk250** · 05-19-2017, 10:09 AM

That double wall catalytic converter looks like it was a challenge. But the end results will pay off. Rejetting will be needed. On the Brozz it might be easier just to cut it off and put a piece of pipe.

Azhule · 05-19-2017, 10:13 AM

Did you remember to grind down the mountain welds on the inside of the header pipe (engine side)... most of these exhausts also have several huge crappy welds on the inside of the pipe that need ground down and circled out a bit... can get upwards of 30% bigger diameter on the pipe depending on how bad those welds are... our bike had one that was extremely restricted

MOTOXtreme · 05-19-2017, 10:26 AM

Quote:

Originally Posted by JerryHawk250

That double wall catalytic converter looks like it was a challenge. But the end results will pay off. Rejetting will be needed. On the Brozz it might be easier just to cut it off and put a piece of pipe.

Yes I agree, I thought the same thing. If I had pipe there to work with i would have.

Quote:

Originally Posted by Azhule

Did you remember to grind down the mountain welds on the inside of the header pipe (engine side)... most of these exhausts also have several huge crappy welds on the inside of the pipe that need ground down and circled out a bit... can get upwards of 30% bigger diameter on the pipe depending on how bad those welds are... our bike had one that was extremely restricted

Hmm, i peeped in there but didnt see anything alarming. Actually the factory welds looked great everywhere I inspected.

Megadan · 05-19-2017, 10:36 AM

If you are worried about the welds being ugly after doing this sort of work, then take a flap disc and smooth out the welds a bit before you paint it. If your welds are good, then you could take the excess bead down to flush and it will never look like it was welded in the first place. Otherwise, header wrap and call it good.

**JerryHawk250** · 05-19-2017, 10:40 AM

Quote:

Originally Posted by MOTOXtreme

Yes I agree, I thought the same thing. If I had pipe there to work with i would have.

I would of done the same but didn't have a piece of pipe either.

Azhule · 05-19-2017, 10:58 AM

"Grinder and Paint"

....

"Make me the welder I ain't"

Here's a pic of what I was talking about... ours wasn't the worst I have seen but it was still really bad

Just horrid on the inside of my factory pipe

ground it down and made it round...

05-18-2017, 10:03 PM	#2
dpl096 Join Date: Sep 2015 Location: East Central Hellinois Posts: 1,344	I don't recall who but someone else removed their cat too but the cut a panel out on the engine side of the body and then dug the material out. Welded the panel back on and from the outside no one can tell it was modified. Seems to me he was from Alabama and ended up selling the Hawk over registration/title issues with the state. __________________ ************************************************ * " Time you enjoy wasting, is not wasted." - John Lennon “I predict future happiness for Americans, if they can prevent the government from wasting the labors of the people under the pretense of taking care of them.” ― Thomas Jefferson "If you don't know where you're going any road will take you there" ....George Harrison song
	0

05-18-2017, 10:25 PM	#3
BigWeld Join Date: Nov 2016 Location: East Pembroke, NY Posts: 301	Hey! I removed my Brozz's cat today, too! __________________ Rides a 2016 Bashan 18C with Blue PlastiDip, piped and jetted, USB charger, real-time digital volt meter, faux carbon fiber handguards, 5 COB led headlight upgrade, auxiliary led light bars, and an MSR shift lever with new grips, T6 aluminum handlebars anodized in blue, polished handlebar brace, decals, HD Unibear chain and spoke covers waiting on the always-full mod shelf......
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05-19-2017, 02:09 AM	#6
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	It'll most likely need a couple of sizes bigger on the main jet after a cat-ectomy. __________________ 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
	2

05-19-2017, 02:35 AM	#7
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,261	since you had the pipe open why did you not turn the cat chamber into a power bomb ? .. __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
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05-19-2017, 10:09 AM	#10
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,554	That double wall catalytic converter looks like it was a challenge. But the end results will pay off. Rejetting will be needed. On the Brozz it might be easier just to cut it off and put a piece of pipe. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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05-19-2017, 07:00 AM	#8
old kid Join Date: Feb 2017 Location: NY Posts: 170	you can do this in one cut if you cut the cat. converter in the center and remove the two halves, i punched a 1/2" drill thru them and pulled the rest out with vise grips. I would also suggest installing the pipe back on the bike and tack welding the two halved back together. make sure they are where they need to be. also some black heat wrap around the header pipe will cover it up if your worried about how it looks.
	0

05-19-2017, 10:13 AM	#11
Azhule Join Date: Dec 2015 Location: CO Posts: 1,525	Did you remember to grind down the mountain welds on the inside of the header pipe (engine side)... most of these exhausts also have several huge crappy welds on the inside of the pipe that need ground down and circled out a bit... can get upwards of 30% bigger diameter on the pipe depending on how bad those welds are... our bike had one that was extremely restricted __________________ "Think as you like... but this self proclaimed Professor is always right" - Buckshot "You never know what someone is hiding beneath their smile..." - NinjaTom - R.I.P.
	1

05-19-2017, 10:36 AM	#13
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 7,991	If you are worried about the welds being ugly after doing this sort of work, then take a flap disc and smooth out the welds a bit before you paint it. If your welds are good, then you could take the excess bead down to flush and it will never look like it was welded in the first place. Otherwise, header wrap and call it good. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	0

05-19-2017, 10:58 AM	#15
Azhule Join Date: Dec 2015 Location: CO Posts: 1,525	"Grinder and Paint" .... "Make me the welder I ain't" Here's a pic of what I was talking about... ours wasn't the worst I have seen but it was still really bad Just horrid on the inside of my factory pipe ground it down and made it round... __________________ "Think as you like... but this self proclaimed Professor is always right" - Buckshot "You never know what someone is hiding beneath their smile..." - NinjaTom - R.I.P.
	0