Has anyone here punched out a cat??

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Wicked Webby

Wicked Webby

Right is Harder than Wrong.
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Hey all you wrench turners,

I know of some racers that have done this on their rides(with good results..For track use only of course!!!). I was wondering if anyone has done it here on the FJR... Most folks that have done this, along with slip-ons, rave about it being the poor persons version of a full system.. Properly tuned of course...

Anyone have 1st hand knowledge of this mod??????

WW

 
Has anyone here punched out a cat??,

Yeah, but you gotta use gloves because they'll scratch you pretty bad.

 
Wicked Webby said:
Hey all you wrench turners,
I know of some racers that have done this on their rides(with good results..For track use only of course!!!). I was wondering if anyone has done it here on the FJR... Most folks that have done this, along with slip-ons, rave about it being the poor persons version of a full system.. Properly tuned of course...

Anyone have 1st hand knowledge of this mod??????

WW
Click to expand...
Not sure, but i think i've seen a discussion along these lines before somewhere on this forum, and the conclusion was if i remember that it's a lot cheaper and easier to buy a set of slip-ons and keep the OEM cans stock.

 
Powerman,

Glad to hear that.

I plan to do the same,

How did u do yours?? Any tips or advice??

Thanx,

WW

 
For the cost of an aftermarket header, I'd hang onto the stock cat header in case you ever need/want to return to stock. I sure the heck wouldn't want to have to buy one of those. 729.77 at Ron Ayers right now... If you were absolutely certain that you were not returning to stock you could likely sell your stock header and cans and almost pay for the full holeshot or muzzy system.

 
I wanted to hold onto the stock pipe, but couldn't find another at the time.

I used a thin cutoff wheel to cut the holes like the picture, then there are little round tits on the cat that need to be drilled/ground out to get them to come out. Put the plates back on and TIG weld them. A plug and washer can be found at the auto parts store to plug the O2 sensor hole.

I think it was maybe 18mm?

 
Powerman said:
I wanted to hold onto the stock pipe, but couldn't find another at the time.
I used a thin cutoff wheel to cut the holes like the picture, then there are little round tits on the cat that need to be drilled/ground out to get them to come out. Put the plates back on and TIG weld them. A plug and washer can be found at the auto parts store to plug the O2 sensor hole.

I think it was maybe 18mm?
Click to expand...

I guess the good thing about your setup is from outward appearances, it's stock. Then you could remove the ends of the stock exhaust cans and core them out with this kit: Bike Johnny Kit

That way you can mess with the noise Nazis that are trying to pass those laws that the pipe must be OEM.

 
Last edited by a moderator:
Or, you could cut the DOT patches outta a set of crashed cans, weld 'em onto those fishtails ya always wanted. Like anyone who's handing out tickets would know.

 
Ok,

I got a question regarding this. Generally speaking, does removing the FJR's cats cause the engine to run leaner or richer? Or can the 02 sensor handle this type of change??

Since I brought this up, with regards to the 02 sensor.. Does anyone know if the FJR's 02 sensor does fuel ratio adjustments all through out the rpm curve or only at idle and lower rpms??

Thanks,

WW

 
Wicked Webby said:
Since I brought this up, with regards to the 02 sensor.. Does anyone know if the FJR's 02 sensor does fuel ratio adjustments all through out the rpm curve or only at idle and lower rpms??
Click to expand...
That's a really good (not great) question.

A great question would be one that I know the answer to... :rolleyes:

 
Cats have no effect on whether the engine runs rich or lean-they only deal with what is fed to them in the exhaust stream. They do offer a slight amount of restriction to flow (backpressure) which the engine management systems deal with, as do they deal with the removal of said restriction. The 02 sensor deals with off idle fuel mixture until WO throttle, when the ECM goes to full pulse on the injectors.

 
Last edited by a moderator:
radman said:
Cats have no effect on whether the engine runs rich or lean-they only deal with what is fed to them in the exhaust stream. They do offer a slight amount of restriction to flow (backpressure) which the engine management systems deal with, as do they deal with the removal of said restriction. The 02 sensor deals with off idle fuel mixture until WO throttle, when the ECM goes to full pulse on the injectors.
Click to expand...

Rad,

Doesn't the ECU operate closed loop at idle too (like a car)?

 
Fred W said:
Rad,
Doesn't the ECU operate closed loop at idle too (like a car)?
Click to expand...
Yup, but idle mix is a predetermined figure, not part of the 02 loop. This is why TPS adjustment is critical (well, one of the reasons) as well as idle speed. I should add that when one adjusts the CO settings via the onboard data interface, ala Barbarian, you are fine tuning idle mix-idle CO is likely where the factory set them.

 
Last edited by a moderator:
radman said:
Fred W said:
Rad,
Doesn't the ECU operate closed loop at idle too (like a car)?
Click to expand...
Yup, but idle mix is a predetermined figure, not part of the 02 loop. This is why TPS adjustment is critical (well, one of the reasons) as well as idle speed. I should add that when one adjusts the CO settings via the onboard data interface, ala Barbarian, you are fine tuning idle mix-idle CO is likely where the factory set them.
Click to expand...
Gotcha, so then I suspect that modifying the CO setting via the barbarian mod will only effect the mixture at idle. Not really at cruise, which is off idle, where the lean surge/stumble is usually felt.

 

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