Cat removal on my '17 ST " how to"

Niterunnr

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Jul 2, 2019
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Irvine, CA
I have the same concern about “consequences.” Looking to buy a used 2018 ST with deleted CAT. Will it pass California emissions?
 

Niterunnr

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Jul 2, 2019
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Location
Irvine, CA
Looks like Cali doesn’t smog motorcycles, (I just moved), so CAT delete will likely be okay. Would an aftermarket header be better? I don’t want louder pipes or extra pollution OR to smell like exhaust each time I ride. Maybe I should replace the factory header with the CAT?
 
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ballisticexchris

Guest
Boy that fab job you did sure does bring back memories!! Not my cup of tea as far as modifications go. But you did a fantastic write up and how to. FWIW, I used to run a really nice Miller combo TIG/SMAW/MIG machine in my younger days. Nowadays I have just a good old Harbor Freight SMAW inverter welder that works really well with 1/16"- 3/32" 6013 rod.
 

twinrider

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Sep 28, 2011
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Yokohama
Looks like Cali doesn’t smog motorcycles, (I just moved), so CAT delete will likely be okay. Would an aftermarket header be better? I don’t want louder pipes or extra pollution OR to smell like exhaust each time I ride. Maybe I should replace the factory header with the CAT?
I put an Arrow header on my 2nd S10 and left the muffler stock. It still passes the smog inspection and the bike pulls noticeably harder. It was flashed before I did this mod.
 

Clawdog60

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Nov 14, 2018
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560
Location
east central "ILL"
Traded my Harley at the dealership with these mods and more. They cut me a check and it paid for my Super Tenere outright. If the dealer won’t work on your bike you are at the wrong dealership. They make money fixing bikes and usually won’t turn away Business.

If some one is willing and brave enough to try these mods then I applaud their efforts. I did it with my Harley and I am now letting others light my path so things go smoothly.
I could see a problem if you’re in California or a big city with emissions testing. I don’t think they test bikes but that could change any day.
 

Niterunnr

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Jul 2, 2019
Messages
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Location
Irvine, CA
I put an Arrow header on my 2nd S10 and left the muffler stock. It still passes the smog inspection and the bike pulls noticeably harder. It was flashed before I did this mod.
Thanks twinrider, I might go that route; looks like arrow headers about $300USD. I’ll research the flash and PCV as well. I replaced the full exhaust on my street bike, but my current ADV (DL650) I left completely stock and have really enjoyed it, so I wasn’t in a hurry to mod the S10. This used offering is otherwise a good deal. I’m just nervous about the oem exhaust being tampered with so I can’t swap back.
 
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RonH

Guest
Here in Colorado we don't have smog check on motorcycles thankfully, but it will come sooner or later. Trouble with gutting the cat is even if a vehical passes with near zero emmisions, it will fail here because they use an infrared thermometer to check the exhaust temperature at the cat. If it's not blazing hot they know the cat is gone and you fail. As I said, not on motorcycles yet. Good job for sure in removal.
 

GearheadGrrrl

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Mar 12, 2015
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Minnesota, USA
Since VW got caught cheating on emissions and paid billions in fines and damages, every manufacturer and dealer is running scared. In the big truck market Daimler (Freightliner, Western Star, and Mercedes) has nearly half the market and they are telling their dealers they cannot work on emissions deleted trucks or accept them in trade. The catalytic converter is one of the most efficient emissions control devices, it ain't worth trashing, especially if you later have to expensively replace it.
 

twinrider

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Yokohama
Thanks twinrider, I might go that route; looks like arrow headers about $300USD. I’ll research the flash and PCV as well. I replaced the full exhaust on my street bike, but my current ADV (DL650) I left completely stock and have really enjoyed it, so I wasn’t in a hurry to mod the S10. This used offering is otherwise a good deal. I’m just nervous about the oem exhaust being tampered with so I can’t swap back.
I don't think you need a PCV if your flash compensates for the greater airflow. My new S10 runs great with the flash alone.
 

Ramwyn

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Nov 3, 2018
Messages
32
Location
Wales, UK
Well done on the how-to. I've been thinking of exhaust mods myself, either de-cat or different silencer so I'm looking forward to hearing how the bike performs after this mod.
 

lukasteam

Life is beautiful !!!
Joined
Sep 22, 2013
Messages
155
Location
Naperville , IL
So last weekend I really got to feel how the bike performs with removed cat .
Remember and have in mind that I have Anthony's reflash for the full Arrow system , but I still have stock can . Before cat removal I absolutely hated Anthony's reflash and it felt even worse than stock , but now with cat removed it's adifferent story . I want to get a more open aftermarket can to open it even more . On a weekend I rode the bike in many different circumstances , on an interstate , downtown Chicago filtering through traffic , you name it I did it . All rpm's all speeds , etc .
This is what I noticed :
1. Bikes takes a little longer to warm up
2. Little less infamous surging while warming up , now it's barely noticeable .
3. Motor runs so much smoother at the idle and while running through out the room range .
4. It revs faster , blip the throttle and rpm jump up noticeably faster than it did with cat .
5. Engine runs cooler and when you done riding it cools off so much faster as well .
6. Gas mileage went down about 1.5 mpg . Also might slightly be because I enjoy the bike so much more it wakes up a little hooligan in me sometimes which of course transfers to the throttle .
7. No back popping what so ever ( just remember I have a re flash , but I think stock ECU would be able to adjust to it no problem )
8. Exhaust note is deeper , but not much louder , maybe by 4-5 db's or so , if that .
With all this experience I'll tell you my opinion guys : I consider this a must do mod . Yes , that's how much I think it improves the rideability and performance of this bike .
 

lukasteam

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Sep 22, 2013
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Naperville , IL
Admittedly great work, but does it help the environment or not? :D
I think we all know that it doesn't . I look at it this way : bikes are already low emissions vehicle , no smell of gas out of my exhaust what so ever . If we really want to help out mother Earth with that , we should all get electric bikes altogether ... but then again , how are you planning to go adventuring to the middle of nowhere with the battery ? I don't feel that confident , so I think for another decade or so we stuck riding our eternal combustion beasts all around the world .
 
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Wallkeeper

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what kind of wire did you use to fill the weld?
 
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