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Removing the cat on an 18' GSXR 750

10397 Views 17 Replies 9 Participants Last post by  aTahmission
I just bought a new GSXR 750 and I bought a two brothers exhaust. I am told that the catalytic converter is responsible for a lot of noise dampening. I want to get rid of it... I have seen some cat deletes for my bike but only for the M4 exhaust like the one below:

https://www.ebay.com/i/191132369017?chn=ps

Has anyone done this on a GSXR 750 with a two brothers exhaust? Anyone think the above cat delete would fit / work?

Thanks!
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Just a friendly heads up: be prepared for a boatload of opinions on whether or not people should remove smog equipment from a bike. Just saying.
Just a friendly heads up: be prepared for a boatload of opinions on whether or not people should remove smog equipment from a bike. Just saying.
Uh oh... hopefully it's clear I'm only asking how to do it not if people think it's a good idea...
Uh oh... hopefully it's clear I'm only asking how to do it not if people think it's a good idea...
I'm not trying to put words in anyone's mouth...but it has been a heated topic in the past, as some see the practice as a middle finger to the environment. I'm sure you mean no harm my friend.

Where do you live, and are emission controls required there? They are where I live (Seattle) but in rural areas they are not.
Hi Hillbro

Many riders purchase after market exhausts for their motorcycle and find that the bike no longer rides smoothly through the rev range. Suzuki have spent a lot of time and money setting up the exhaust system for your bike, exhausts are much more than a pipe. You should always take professional advice from someone who has already fitted this exhaust to the same model bike, then dyno tested it. You should add the cost of professional dyno testing and engine mapping when adding an exhaust to a sports bike.

Many people end up putting the old exhaust back on their bike to solve the problems introduced by the new one.
Found the best way usually to eliminate the CAT is get an aftermarket exhaust designed for your system .. Only time I ever strayed from this was on my present Indian Chieftain .. Mainly Because it being a New Make, A Full System Exhaust was over the moon in price, with not the best of results in performance either .. So ended up doing the Cat elimination on Stock Headers and then got Slip Ons, A/C and Tuner all under one roof with Fuel Moto who have been in the performance business for many years ..
I live in Virginia. I am pretty sure just putting on a two brothers exhaust like I did when I bought the bike was technically illegal. I got a "unsafe passing" ticket on the bike (for driving around a parked car on the road) and they state police didn't even look at it. Had no idea about the environmental issues... My first bike was a used GSXR 600 and it already had the cat removed and a two brothers exhaust slip on installed so that is what I came to expect. I was pretty disappointed with the stock sound of my new GSXR750 so that's why I am running down this rabbit hole.

Thanks for the replies so far! I don't think there are actually a proper cat delete for my bike / year yet? My dealership told me they would only install a full system and then quoted my like 2-3k...yikes.
I would say to try the 2 Bros slip-on first to see how much louder it is. They are known for being one of the louder aftermarket slip-ons and usually have a removable baffle that you can take out if it isn't loud enough for your taste. Removing the cat seems like it would create more issues than it is worth, imho...
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This link might interest you. It's for a Honda though. I had to have Google translate to English. But I took that whole ugly unit in the first picture off my 13 cbr1000. I also disconnected the servo motor. You have to. No engine codes from that even though they have an aftermarket gadget that fool's the bikes computer into thinking it's still there. I installed a bmc filter and 2 Bros carbon slip on and love the sound! Especially, on a cold start. It is loud and sounds bad ass. Obviously, you know the 2 Bros sound. I don't think there is anything like it. Yoshi sounds "weak" to me and a lot of guys like that. But, as mentioned I did the pc5 with a Dyno tune. It is necessary if you want the BEST from your bike. Bike runs great even in the city in the lower rev range. Better than when it was stock.
Why wouldn't that work for your bike? Or, what you can do is buy all new headers. Saw them for around $300. Then add whatever slip on you want. I would just add the slip on first and see how you like it. But whatever you do, make sure you get everything done together if you go to get it tuned

https://bikepost.ru/blog/38286/Iz-stoka-v-prjamotoki.html
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You may want to check that you don't invalidate your warranty doing so.
No need to check, 100% guarantee if anything engine related goes wrong under warrantee they will point at that exhaust mods and deny the claim.

You may want to check that you don't invalidate your warranty doing so.
No need to check, 100% guarantee if anything engine related goes wrong under warrantee they will point at that exhaust mods and deny the claim.
Exactly, putting a slip on is one thing, removing the CAT is another, fine once the bikes paid for and out of warranty but I personally would like it and lump it till then, lets face it unless your having the bike tuned you really are just doing it to make more noise.
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Exactly, putting a slip on is one thing, removing the CAT is another, fine once the bikes paid for and out of warranty but I personally would like it and lump it till then..

Lets face it unless your having the bike tuned you really are just doing it to make more Noise.
Actually my Catless Pipes are pretty mellow just a bit louder than stock, but Main Reason eliminated it was Heat, but also did Tune it with a PVCX and Runs far better, smoother and even better MPG .. No Argument on the Warranty thing as far as the engine goes, but if have an ABS or Wheel Bearing failure and they want to blame the Exhaust we will have to fight about those ..
Actually my Catless Pipes are pretty mellow just a bit louder than stock, but Main Reason eliminated it was Heat, but also did Tune it with a PVCX and Runs far better, smoother and even better MPG .. No Argument on the Warranty thing as far as the engine goes, but if have an ABS or Wheel Bearing failure and they want to blame the Exhaust we will have to fight about those ..
But to be fair its not something I would do on a brand new bike, with things like Harley Davidsons you can get away with it as long as they do the work, you mess with them you void the warranty, The guy with the GSXR is doing it for more noise, a slip on would give you more than enough noise, which you could get away with (talk to the shop) but taking out the cat is going to invalidate a bike warranty, let be honest if your bike engine went south your going to be in a bad place, the shop wont touch it, the manufacturer wont touch it, and all because you wanted some more noise, personally I would wait till the warranty was over and then stick it into a tuner shop so they can do it properly.
Actually my Catless Pipes are pretty mellow just a bit louder than stock, but Main Reason eliminated it was Heat, but also did Tune it with a PVCX and Runs far better, smoother and even better MPG .. No Argument on the Warranty thing as far as the engine goes, but if have an ABS or Wheel Bearing failure and they want to blame the Exhaust we will have to fight about those ..
These are pretty much the reasons I choose a full delete system for my bike. Not only was it heavy (I shaved something like 14 lbs) but the bike runs super hot otherwise, and I worry about long-term durability. Additionally, Ducati is renown for having constant failures in the exhaust valve within the Cat, and indeed, mine seized up after less than 3,000 miles. The exhaust isn't that loud with the sound baffle in, but it makes just too much noise with it removed. Removing the sound baffle would have a bigger impact on removing the cat-con. I'm not too worried about my warranty. My 2 years is almost up, so c'est la vie.
But to be fair its not something I would do on a brand new bike, with things like Harley Davidsons you can get away with it as long as they do the work, you mess with them you void the warranty, The guy with the GSXR is doing it for more noise, a slip on would give you more than enough noise, which you could get away with (talk to the shop) but taking out the cat is going to invalidate a bike warranty, let be honest if your bike engine went south your going to be in a bad place, the shop wont touch it, the manufacturer wont touch it, and all because you wanted some more noise, personally I would wait till the warranty was over and then stick it into a tuner shop so they can do it properly.
I think that's actually the other way around now. Harley has had their hand slapped by the EPA, so they refuse to modify the exhaust (I'm not sure the parameters of "modify") at the dealership. I spoke with the service manager at my Ducati dealership about this, and he told me it was basically down to their discretion as to what they report to Ducati. Basically, if my exhaust mod wasn't directly responsible for a failure, he saw no reason to tell them that I had changed anything. Now, I didn't go with a full system with an upmap. That would be impossible for me to hide from the OEM.
I think that's actually the other way around now. Harley has had their hand slapped by the EPA, so they refuse to modify the exhaust (I'm not sure the parameters of "modify") at the dealership. I spoke with the service manager at my Ducati dealership about this, and he told me it was basically down to their discretion as to what they report to Ducati. Basically, if my exhaust mod wasn't directly responsible for a failure, he saw no reason to tell them that I had changed anything. Now, I didn't go with a full system with an upmap. That would be impossible for me to hide from the OEM.
That is not the case in the UK with Harley Davidson, however the key part of what you said in regards to the Ducati dealership " If my mod wasn't directly responsible" A slip on you would get away with if your engine did go south then you just swap over the slip on. The problem with some dealership they will use any excuse to blame the customer.
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That is not the case in the UK with Harley Davidson, however the key part of what you said in regards to the Ducati dealership " If my mod wasn't directly responsible" A slip on you would get away with if your engine did go south then you just swap over the slip on. The problem with some dealership they will use any excuse to blame the customer.
Absolutely, which is why I like to find a dealer I feel is willing to advocate for his customer. I worry that with the mega-dealerships selling multiple makes, any chance for advocacy becomes slim. We do have a law in the states intended to make the processing of warranty claims more fair (Magnuson–Moss warranty act) for the consumer. Of course if it is an obvious case of the customer's modification causing the failure, then he's SOL, but it does give us some protection from slippery manufacturers trying to avoid responsibility.
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