z900 A2 Cat Delete

[Ryan Kerry]

Hi,

I have an A2 compliant z900 with stock headers and an SC-project slip on. I have been thinking about getting new headers but they look to be very expensive. An alternative would be to just get a mid pipe and cut the cat off.

However, I am curious to know if the bike would then need retuning in order to smooth the fuelling out? and how easy this process may be?

Any ideaas?

Thanks

[Easy-X]

Might we know why you want such a modification? A more free-flowing exhaust might* increase the power output of the engine - however slight - and then it won't be A2 compliant.

*Adding 2 or 3 bhp isn't going to make much odds to most bikes but AFAIK the A2 is a hard power limit.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Ryan Kerry]

I would only want the modification for a better sounding exhaust - not the increased power. Like you said it would only be a slight increase, if any at all.

[Nobby the Bastard]

[Ryan Kerry]

Shush Nobby

[Nobby the Bastard]

[Capt Sisko]

[Easy-X]

Let's sum this up politely: why not just keep your head down for the next 24 months? A little self-restraint might be therapeutic
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Ryan Kerry]

I hadn't realised I was asking psychoanalysts for bike advice nor am I looking for a deeper understanding of the law.

It's simply wanting to enjoy the sound of my bike a little more. The consequences are my responsibility and despite how truly appreciative I am of your concerns, the part about the retuning is of interest

Yours sincerely

[Nobby the Bastard]

[Easy-X]

[Nobby the Bastard]

[MarJay]

You will either add power or ruin the engine. Honestly, no joke. If you remap a decatted bike you'll probably gain 10-15bhp. If you don't remap you could run the bike dangerously lean and then hole a piston.

When you remove cats you NEED to remap. The bike won't cope with that big a change in fuelling without being fettled.

The noise thing is ridiculous, as if you decat a bike and have a race can you may find the noise is not just loud that it's ear bleedingly unpleasant. My GSXR750 had a dual exit GP style exhaust on it when I got it, with the cat. With that exhaust honestly it was painful and unpleasant. Without the cat? I suspect it could be measured on the richter scale.

If you've already got a slip on, leave it at that.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Polarbear]

Can you legally decat a bike? I thought it was illegal to decat a car? Or is that remove the DPF from a diesel? Too much legislations nowadays.
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Triumph Trophy Launch Edition

[MarJay]

[Ryan Kerry]

Aha I see and thank you finally for the advice - despite the passive aggression

I have done some reading based on the deterrence from you guys and have read that I am able to keep the cat but remove the 'breadbox' and just add a shorter mid pipe.

Regarding remapping, if i keep the cat, is it still necessary?

Thanks

[Easy-X]

Removing restrictions = more flow = more lean without a remap.

Quantifying how much each individual component affects the overall system? You can only go by experience and forum hearsay. You can be certain the original system from the manufacturer balances noise, performance and emissions well enough for the engine to last the warranty period

To echo MarJay: you may be disappointed with the results. My first attempt with the XSR left me with a two wheeled hammer drill Quite a lot of experimentation went into balancing tone and loudness. I now have quite a selection of Chinese knock-off end cans in my shed
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Fullers1845]

[blurredman]

https://c.tenor.com/qLcAy8rubBAAAAAC/tenor.gif
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CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1973 MZ ES250/2 - 17k. , 1979 Suzuki TS185ER - 9k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 38k, 1989 MZ ETZ251 - 49k

[Nobby the Bastard]

In gods name why would you want to restrict a 130 bhp bike down to less than 50?

Pretty sure you can't even legally make a z900 an A2 restricted bike.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[rpsmith79]

[Ste]

The A2 version has a 8500rom restriction when in A2 mode so you're not going to get the noise you're wanting regardless of what exhaust parts you upgrade.