Remove cat from STD Sport silencer?

[Bruno55]

Hi everyone out there,I have been watching this site for quite some time,so thought it was time to jump in.
Money being a bit tight this time of year and the bike being under about a foot of snow,I wondered if anyone had tried removing the cat from the standard 1200 Sport silencer.I like the way the stock can looks (some after-market cans seem too small and out of proportion to me).a bit less weight and better breathing would be a good thing.And for the bike also!

 

[kiwi dave]

Notwithstanding the legal and green aspects of doing so, I would proceed with caution. You are assuming that the bike will run better, but it might run like a pig. Be sure you can reverse the procedure, or have a spare. Modern exhaust systems are not that simple.

 

[Bruno55]

No need for a cat. in the UK legally.I have not seen an after-market muffler for the Sport which has a cat. so I would think They must run OK (as the reports say).
I have had quite a few Guzzi's over the years and they have all run better with a free-breathing exhaust.I do not want more sound but this is basically an old fashioned design of engine which I do not think benefits from a cat. which was really designed for cars and originally developed in California to work in a climate with a higher ambient temperature than the UK.

 

[Martin]

I have not seen an after-market muffler for the Sport which has a cat.

Quat-D sells them without and with a (removable) cat.

 

[GrahamNZ]

Bruno55
I agree with kiwi dave in advising caution when altering the exhaust system on modern bikes with FI and no way to alter the ECU mapping. While the basic architecture of modern Guzzis harks back to Carcano's original concept, that's about all they have in common with older models.

Still, if you do remove the cat we'll all be interested in your findings.

My first Guzzi, a 2001 V11 Sport, needed new silencers after one "went all flat and scratched" so I fitted some beautifully made Neptune ones in black chrome. They looked and sounded wonderful and saved a lot of weight but the bike wouldn't accept more than a whiff of throttle at lower revs until some back-pressure inserts were added. I have no idea what effect those silencers had on the fuelling mixture and I do hope the bike is still running well for its current owner........

Having made several exhaust systems in my time for carbed bikes, I have an inkling about how difficult it is to get fuelling and an exhaust to work satisfactorily. Now I never alter those aspects on modern bikes. The tales of woe from Buell owners who insist on altering things are everywhere, despite there being a programme available enabling fuel mapping to be altered........If you know what you're doing. which I don't.

IMHO the best way to get a bike to perform well is to ensure it's tuned correctly, has good tyres, and the suspension set up for your weight and riding conditions. Only when full throttle isn't enough is it time for more performance.

 

[GTM®]

The Breva/Sport/Norge/Stelvio, etc. mufflers have a series of steel baffles alongside of the cat-con. They can be removed, but are *VERY* time/cost intensive to do while keeping it looking acceptable, and the Sport has the fragile carbon-look wrap.

Graham, I am capable of altering any parameter on the ECU, so I'll take it you mean there is no easy/cost effective way to do so... if so, that is somewhat true. There are many ways to revise fueling posted in the main Chat section, including moving the sacred screw and resetting the TPS, which is often done by the dealers who install aftermarket mufflers.

 

[GrahamNZ]

Graham, I am capable of altering any parameter on the ECU, so I'll take it you mean there is no easy/cost effective way to do so... if so, that is somewhat true.

Yes Todd. That is what I meant.

There are many ways to revise fueling posted in the main Chat section, including moving the sacred screw and resetting the TPS, which is often done by the dealers who install aftermarket mufflers.

While I can understand that that method can fool the ECU into delivering an overall richer or leaner mixture and altered ignition timing to suit, it isn't really altering the fuel mapping. I wonder if said dealers use an exhaust gas analyzer to verify the good sense of their alterations?

 

[kiwi dave]

I am capable of altering any parameter on the ECU, so I'll take it you mean there is no easy/cost effective way to do so... if so, that is somewhat true. There are many ways to revise fueling posted in the main Chat section, including moving the sacred screw and resetting the TPS, which is often done by the dealers who install aftermarket mufflers.

Todd, a good example is the 2-into-1 colostomy bag replacement you fitted to my Breva. While it appeared to improve the low-mid end performance, the exhaust occasionally emitted a loud explosion when closing the throttle, much to the alarm of occupants in nearby cages. It got to the stage where I was deliberately avoiding closing the throttle completely, in fear I was going to be shot at in retaliation!

Resetting the TPS had no effect. An upgraded map at last year's nationals cured the problem, albeit at the slight increase in fuel consumption. A happy ending, but without an Axone, this would not be possible for the average owner.

 

[Brushwarrior]

Todd, a good example is the 2-into-1 colostomy bag replacement you fitted to my Breva. While it appeared to improve the low-mid end performance, the exhaust occasionally emitted a loud explosion when closing the throttle, much to the alarm of occupants in nearby cages. It got to the stage where I was deliberately avoiding closing the throttle completely, in fear I was going to be shot at in retaliation!

Resetting the TPS had no effect. An upgraded map at last year's nationals cured the problem, albeit at the slight increase in fuel consumption. A happy ending, but without an Axone, this would not be possible for the average owner.

I have had a mistral system on my Breva 1100 since last Sept and all seems ok for now.(baffle in as described by Guzzi dealer as a "tepid" version. Yet to let dealer haywards or Max moto near when annual service comes around. So i presume a dose of Axone is in order? I know Ian who has a mistral can for his 1200 sprt, pops a few bangs :-D Can i make the assumption of a choice of maps is available but only if you have the Axone equipment?

 

[PP-1753]

I am almost at the point where I get the boring bits out and give it a go. I am sure there is more music to be had by doing so...