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Online hector

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Re: De-cat pipes at last.
« Reply #40 on: July 18, 2018, 08:22:27 AM »
*Originally Posted by Yox [+]
It only injects air when the throttle is shut I think? If so no fuel would get adjusted.

hi yox,, quite possibly,,,
but why then when having a custom fuel map set up on a dyno do they block it off or clamp the vacume pipe from the valve, surely its so they get a accurate fuel/air reading so it must affect it under throttle ??
just thoughts from the top of my head,,
 :002: :002:

Offline 9SecVmax

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Re: De-cat pipes at last.
« Reply #41 on: July 21, 2018, 04:02:27 PM »
*Originally Posted by hector [+]
just a thought here about using block off plates for the pair valve/ais unit,
the valve injects fresh air in to the exhaust gasses to dilute the gasses,, the o2 sensor in the exhaust is set up to read the gasses and adjust fuelling to suit,, so if you remove the air being injected then the gasses will seem richer so the o2 sensor will weaken the fuelling ,,,,, or am I off base on that one ??  like I said. just a thought  :002:

I bought a kit on eBay that disables and bypasses the pair valve. Came from Greece. It comes with plates and the bypass plug. Pretty nice actually.

That's most likely the cause of the popping. CLEAN Air is injected into the exhaust stream to IGNITE unburnt fuel on deceleration. Emissions. This is the pop you hear.  The additional heat generated by this ignition further heats the converter/catalyst making it more efficient.

Don't disable this if leave leave your cat in place. Removing it allows unburnt fuel to enter the catalyst and weaken it.

ECU reflashing does not disable the pair valve. Just the FI Error Code.  The bypass adapter plug is just a resister but a good idea if you don't reflash.

Yep. The extra oxygen injected can skew the AFR readings (lean) while tuning. It needs to be bypassed temporarily. Again, if your are tuning with the catalyst in place.
« Last Edit: July 21, 2018, 04:30:02 PM by 9SecVmax »

Offline Floydsz1

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Re: De-cat pipes at last.
« Reply #42 on: July 21, 2018, 06:42:42 PM »
I also have a zrx1200 that I've fitted a full akropovic system along with a k and n air filter, I rejetted it with dynajet kit, when I removed the octopus ( all the pipes etc for the air recirculation system) the kit for that came with block off plates and a bung for the air box. Without this kit it pops back on the overun. Didn't effect the carburetion, with or without the block off kit, it just tidys up the top of the engine, ( less pipework).

Offline peter73

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Re: De-cat pipes at last.
« Reply #43 on: July 24, 2018, 08:07:21 AM »
*Originally Posted by 9SecVmax [+]
... That's most likely the cause of the popping. CLEAN Air is injected into the exhaust stream to IGNITE unburnt fuel on deceleration. Emissions...

The reason for unburnt fuel to reach the exhaust pipes in the first place is that the engine is ruining rich and one possible cause for this has already been suggested by hector. Backfiring is most often the inevitable consequence of DIY mods - I am yet to hear a pop from my stock V.

"Emissions" has turned into the universal explanation used by every DIYer as an explanation whenever he reaches the limits of his understanding of engineering design. But "emissions" is not a bad thing - apart from the obvious benefits, it also means efficiency and fuel economy. You can probably get a negligible increase in torque here and there (by losing it elsewhere) by throwing considerable amounts of fuel into the air (literally) but is that really worth it and do you really feel it or is it mostly placebo?

Offline 9SecVmax

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Re: De-cat pipes at last.
« Reply #44 on: July 24, 2018, 12:38:49 PM »
You are dead wrong.  :760:  :151:

Why would Kawasaki engineers use this apparatus for decades? This is a normal phenomenon in every internal combustion engine when you close the throttle. For God's sake, its on cars as well. You don't hear it all the time on a STOCK bike is because you have a MONSTER catalyst baffling it.

Anybody, just google it if you are curious.

Offline 9SecVmax

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Re: De-cat pipes at last.
« Reply #45 on: July 24, 2018, 01:00:21 PM »
For God's sake.  :760: :760: :760: :760: :760: :760: :760: :760: :760:

PLEASE everyone, watch this:


This guy is considered the ZX14/Busa Master and is well known world wide in DRAG RACING.

STOP the bad information

Online Crosshairs

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Re: De-cat pipes at last.
« Reply #46 on: July 24, 2018, 01:20:45 PM »
*Originally Posted by 9SecVmax [+]
You are dead wrong.  :760:  :151:

Why would Kawasaki engineers use this apparatus for decades? This is a normal phenomenon in every internal combustion engine when you close the throttle. For God's sake, its on cars as well. You don't hear it all the time on a STOCK bike is because you have a MONSTER catalyst baffling it.



100% correct.....you wont hear it with a quiet exhaust and a catalyst....anyone who has ever put a slip on on this or any other bike with a cat bike knows that the cat is one of the best mufflers out there.... a slip on alone makes very little difference in the sound of the motorcycle...but put a decat pipe on and you will hear the difference....



Offline peter73

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Re: De-cat pipes at last.
« Reply #47 on: July 24, 2018, 01:28:26 PM »
I have a video too :-)) I don't think this guy needs introduction.

Offline 9SecVmax

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Re: De-cat pipes at last.
« Reply #48 on: July 24, 2018, 01:50:56 PM »
 :mfr_lol:

Brock Davidson is a SME (Subject Matter Expert) on this topic as he DOES this for a very profitable living. He describes the PAIR system AS IT PERTAINS to motorcycles. He not only describes its operation but gives you an ACTUAL/FACTUAL demonstration.

He also tells you when and when not to touch it and the reasoning behind it.

The Brock's video is exactly what this thread question is about. It will clearly and concisely "clear the air" on PAIR valve theory and operation.

Offline TYKE

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Re: De-cat pipes at last.
« Reply #49 on: July 24, 2018, 02:48:54 PM »
*Originally Posted by 9SecVmax [+]
:mfr_lol:

Brock Davidson is a SME (Subject Matter Expert) on this topic as he DOES this for a very profitable living. He describes the PAIR system AS IT PERTAINS to motorcycles. He not only describes its operation but gives you an ACTUAL/FACTUAL demonstration.

He also tells you when and when not to touch it and the reasoning behind it.

The Brock's video is exactly what this thread question is about. It will clearly and concisely "clear the air" on PAIR valve theory and operation.

And it worked for me .... it's easy to get drawn into a load of bullsh*t with some subject matters, but I must say Brocks explanation was understandable, which is quite an achievement for me  :001:     

Thank you for sharing, very informative  :028:   
Be wary of an old man in a world where men die young

Roger (Rog)

 



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