Removing the Cats

Whooshka

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I know the cats are at the forward edge of the can where the header pipes start to widen. Can the cats be removed without cutting the can? Or ae thy too far back?
 

Mellow

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It wouldn't sound very good... I would get some delkevic pipes then sell your oem ones to recoop some cost and be done with it.
 

Blrfl

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Can the cats be removed without cutting the can? Or ae thy too far back?
Given that the can is welded everyplace parts meet, I'd say no.

Other than losing a trivial amount of weight, what benefit would you get from it?

--Mark
 

SupraSabre

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The stainless covering the pipes is pretty thin. Under the stainless is steel. so you would have to cut through the stainless and the steel, remove the cats and then re-weld it all back together.

Although I've heard of folks going thru the "opened end" to "punch out" the cat, it's really a PIA.

I have '04s and 10 & 12. The 10 & 12 generate more heat at the cats than do the '04s. so, if you have a '08 or newer, to have less Cat area, pick up some '03-'07 mufflers, which would mean, less heat from that area!

And BTW, if ANYONE wants a couple of scratched up '03-'07 mufflers to cut up, stop by and grab a couple! I have about 5 sets of mufflers siting in my back yard. Some are '08-'12, but most are the earlier.
 
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If you do as Mellow suggested, you may want to keep the OEM exhaust until after your next inspection just in case it won't pass inspection in NJ with non-stock exhaust. Keep in mind that replacing the exhaust cans may violate EPA requirements that specify noise emissions of not more than 80 dBA. It says so right in the mufflers. I don't know about this point, but some states may fail motorcycles that have any aftermarket exhaust systems.
 

Mellow

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If you do as Mellow suggested, you may want to keep the OEM exhaust until after your next inspection just in case it won't pass inspection in NJ with non-stock exhaust. Keep in mind that replacing the exhaust cans may violate EPA requirements that specify noise emissions of not more than 80 dBA. It says so right in the mufflers. I don't know about this point, but some states may fail motorcycles that have any aftermarket exhaust systems.
Good point, here in Texas they just say 'sounds nice, here's your sticker' lol
 

ST Gui

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Inspection? What's an inspection??

Here in CA we had mandatory roadside inspections for cars. The CHP would set up a site and wave cars over and run them through some basic inspections. If you passed you got a sticker on the spot. If not you had to correct the error.

I had a mild exhaust leak in a new system I installed on my '62 impala. After fixing it I found and ran through another cite to get my windshield sticker. I was sorry to see them go. It was probably too expensive to maintain and these days it couldn't be seen as arbitrary.

There may be some inspection when registering a custom made vehicle but otherwise I don't remember a bike routine inspection.
 

SupraSabre

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....I don't remember a bike routine inspection.
Only to get a salvaged titled bike back on the road. You have to have a "safety" brake light certificate and then either a CHP or DMV runs your VID.
 
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If you do as Mellow suggested, you may want to keep the OEM exhaust until after your next inspection just in case it won't pass inspection in NJ with non-stock exhaust.
FWIW, there are no more motorcycle inspections in New Jersey... they were pretty much useless anyway.
 
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Here in the Lone Star state, the annual inspection for motorcycles is solely a safety inspection, no emissions check. The past several inspections for me, they didn't even look at the tire wear or check the brakes! Just the lights, brake light, turn signals and horn, and verify the VIN.
 
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Good point, here in Texas they just say 'sounds nice, here's your sticker' lol
Love Texas bike inspections!!! Headlight? Tail Light? Brake light? Turn signals? Horn? Tag light? Got tires on it? Brakes must work 'cause you rode it in. Numbers match the paper. That'll be $17.
 
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I know the cats are at the forward edge of the can where the header pipes start to widen. Can the cats be removed without cutting the can? Or ae thy too far back?
I would leave them alone. The OEM mufflers and cats are there for the environment and to provide performance for the engine. There is a certain amount of backpressure attributed too the cats, this is taken into account with the programming of the ECU. Removing the cats and decreasing the backpressure can actually decrease the low end torque. FI bikes come lean anyway, from the factory, to meet EPA regs.
Increase the flow without any ECU changes you are gonna make a lean bike leaner, make a hot bike hotter, and decrease the low end torque. I am told that some systems, like the one on my Monster, can accommodate for these changes, and I suppose tuners are available for the ST, don't know. You are probably just after a better sound anyway, and IMHO it is just too much trouble and expense to mess with for that.
My old carby Ducati 900ss was rejetted with an open airbox and TBR CF pipes. Now, that was a sound! And I can understand why anyone would like something similar on their bike.
 
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Whooshka

Whooshka

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Thanks for the replies! To address a couple of things... NJ does not have bike inspections anymore. In my opinion a dumb idea, I like to know that rat bike pulling up to the light behind me has working brakes. I was thinking of trying a fuel controller, which would richen things up a bit. So removing the cats would add exhaust flow, they don't change direction of the exhaust scavenging like the baffles do. That paired with a K&N filter would help it breathe. And it wouldn't affect the sound because all the sound baffles are after the cats. I don't want aftermarket, I like the stealthy sound. These are just some ideas I've been bouncing around in my head.
 
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NJ does not have bike inspections anymore. In my opinion a dumb idea, I like to know that rat bike pulling up to the light behind me has working brakes.
But even when they checked brakes at inspection, they only asked you to lock the rear briefly. Not only is the front brake more important, but bikes with ABS wouldn't be able to lock the rear anyway. And then of course, some bike could lock the rear at 5 mph, but might otherwise have near useless brakes.

As for me, I don't miss motorcycle inspections at all.
 

thekaz

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Thanks for the replies! To address a couple of things... NJ does not have bike inspections anymore. In my opinion a dumb idea, I like to know that rat bike pulling up to the light behind me has working brakes. I was thinking of trying a fuel controller, which would richen things up a bit. So removing the cats would add exhaust flow, they don't change direction of the exhaust scavenging like the baffles do. That paired with a K&N filter would help it breathe. And it wouldn't affect the sound because all the sound baffles are after the cats. I don't want aftermarket, I like the stealthy sound. These are just some ideas I've been bouncing around in my head.
The ST1300 has O2 sensors in a closed loop thus many "fuel controllers" will not work well :eek:( BUT its also why removing the cats and air system works so well LOL
Some ideas to mod the fuel map include forcing the loop open which kinda work but really just a O2 sensor wire hack. I have not read or heard of anyone being able to actually change the OEM fuel map. I think becuase the ST1300 runs well already no one has put the effort into even trying to "open up" an OEM CPU
I was going to remove the cats from the OEM but then was given a set of delkevics for free ....... so installed them and disabled the air system.
 

ST Gui

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It seems to me that there is some baffling in some cats to allow the catalytic media to be thoroughly exposed to the exhaust (or vice versa). Of course the ST cats could be constructed similar to the old Thrush Cherry Bomb mufflers— straight through with absolutely no baffling.

The only question— if the cats are successfully removed will the FI be able to compensate for the reduced back pressure especially if an K&N is also used.

I have no reason whatsoever to consider removing the cats from my bike but am interested to see how that works out for you.
 
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Whooshka

Whooshka

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I think FI doesn't care about back pressure. It adjusts air/fuel mix based on exhaust gas, intake temp, and a few other parameters But I don't believe there is an exhaust pressure sensor anywhere that is sending a signal to the ECU.
 

The Dan

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I have aftermarket exhaust and a K/N filter and never had a problem with heat or power. Cats don't effect the O2 sensors so that's not a problem....Knock em out and go for it.
 

Blrfl

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I think FI doesn't care about back pressure.
That would be correct. The engine cares, but that's just physics in action.

You'll find the ECM on this bike supremely uncooperative in the face of attempts to change its behavior. DynoJet offered a PC III for the 1300 when it came out in 2003, but a firmware change in 2004 models rendered it useless and they took it off the market. A handful of people who've tried the Bazzaz add-on have reported good results, but I have yet to see any data beyond runs on the butt dyno.

The thing about trying to hod-rod the ST is that you have to do an awful lot of it for the torque- or power-to-weight ratios to move any appreciable amount. Filling in the flat spot between 3,500 and 4,500 is nice, but the go-fast part of the torque curve is beyond that anyway.

--Mark
 
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Whooshka

Whooshka

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It's not about peak HP and torque. It's about power delivery and drivability. Like getting rid of that flat spot.

And those who have installed aftermarket cans have reduced their back pressure WAY MORE than what just removing the cats would do. Do their bikes run well?
 
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