Ghost hose Gen 1?!?. Help!?
- Thread starter Zukonda
- Start date
Yes, depending ... was it all by itself and unplugged? Was the bike running ok? Block off plates installed?
Def Pair Valve likely suspect.
GenuineChevy39
Registered
Zukonda
Registered
Yes, its plugged purposely by someone. I found that it is supposed to be airbox like you describe. So I guess you are right. But could you please do me the favor and explain to me why this is done? Bypass the Pair valve? Im lost
People bypass the pair valve for 2 reasons-to save weight and to eliminate the "popping" on decal when you have an aftermarket exhaust.
Zukonda
Registered
It was by itself and was plugged. Bike running jumpy, so i was about to change the spark plugs and sync the carbs. Block off plates??
Also mentioning that the bike has installed a k&n airfilter, and a powcom 5.
Zukonda
Registered
Thnx for replys.
It has Yoshi slipons and a k&n airfilter + powcom 5.
I love it when someone asks a a question on a topic I’ve only recently learned about. Like a knowledge test...
@Zukonda
This should begin to answer your question: Secondary air injection - Wikipedia
... about what a PAIR is/does.
Some remove this entire system from their bikes, as it is purely an emissions control function. Removing the whole thing, however, (from a Gen 2 Hayabusa, at least) will cause your bike's system (ECU) to detect a malfunction (as it should) and report a code (called an FI - Fuel Injection - code; you can Google 'Hayabusa FI codes' or just do a search on this forum for that topic to learn more). There are ways to defeat that code as well, but it's more complicated, so many riders opt merely to bypass (as opposed to deleting) the system by "blocking off" certain components within the PAIR system. To do this, you can purchase and install something called, unsurprisingly, 'block-off plates'. You can Google that as well to learn more.
Technically, a properly tuned bike should not be backfiring on deceleration. It's backfiring because a condition is causing the backfire to occur. One common condition is an improper air/fuel ratio (AFR), common because so many riders alter the OEM exhaust setup that came with the bike from the factory. Altering the exhaust can alter the AFR and, in many instances, that altered AFR expresses itself by backfiring upon engine deceleration. It has something to do with unburned gases entering the mufflers (physics + chemistry that far exceeds my intellectual capacity ... kinda like my brain starts to run lean, if you get my metaphor...) Anyway, spend some Internet time exploring this topic and you, too, will know as much as I do.
Just so you know, the reason I fell down this rabbit hole is because getting your bike "Dyno-tuned" helps to optimize the bike's engine performance. In order to get a proper Dyno tune, the PAIR system must be defeated, else the dyno's parameters will be skewed by the extra oxygen being pumped into the bike's exhaust via the PAIR.
I did not plan on writing this much detail. Hope it helps.
@Zukonda
This should begin to answer your question: Secondary air injection - Wikipedia
... about what a PAIR is/does.
Some remove this entire system from their bikes, as it is purely an emissions control function. Removing the whole thing, however, (from a Gen 2 Hayabusa, at least) will cause your bike's system (ECU) to detect a malfunction (as it should) and report a code (called an FI - Fuel Injection - code; you can Google 'Hayabusa FI codes' or just do a search on this forum for that topic to learn more). There are ways to defeat that code as well, but it's more complicated, so many riders opt merely to bypass (as opposed to deleting) the system by "blocking off" certain components within the PAIR system. To do this, you can purchase and install something called, unsurprisingly, 'block-off plates'. You can Google that as well to learn more.
Technically, a properly tuned bike should not be backfiring on deceleration. It's backfiring because a condition is causing the backfire to occur. One common condition is an improper air/fuel ratio (AFR), common because so many riders alter the OEM exhaust setup that came with the bike from the factory. Altering the exhaust can alter the AFR and, in many instances, that altered AFR expresses itself by backfiring upon engine deceleration. It has something to do with unburned gases entering the mufflers (physics + chemistry that far exceeds my intellectual capacity ... kinda like my brain starts to run lean, if you get my metaphor...) Anyway, spend some Internet time exploring this topic and you, too, will know as much as I do.
Just so you know, the reason I fell down this rabbit hole is because getting your bike "Dyno-tuned" helps to optimize the bike's engine performance. In order to get a proper Dyno tune, the PAIR system must be defeated, else the dyno's parameters will be skewed by the extra oxygen being pumped into the bike's exhaust via the PAIR.
I did not plan on writing this much detail. Hope it helps.
Kiwi Rider
Registered
The Dynojet Dynometer needs to have it's own oxygen sensor and a long tube is placed in the exhaust muffler so the calculations can be made re the air/fuel ratio and displayed as a graph on the screen of the dyno's computer.
If you leave the PAIR valve working, it pumps extra air into the exhaust and this upsets the readings needed to tune the air/fuel ratio correctly.
So that is why the PAIR valve must be disabled for dyno readings and tuning.
Zukonda
Registered
Thank you very much for your detaild and explaining answer. I have also googled it a bit more, and are sort of beginning to understand.
Hayabusa Wannabe
Registered
Also @HayaWakened, the exhaust popping on deceleration is not a "backfire" despite that term being ubiquitously adopted by motorcyclists. Backfiring is something really bad. It is combustion at the wrong timing resulting in the explosion blowing out of the valves and into the exhaust or intake. Some form of damage is likely as a result.
To the points above the pair valve provides clean air to the exhaust. The heat and this O2 supply are enough to ignite the excess fuel in the exhaust. Note that this is always going on by design of the PAIR valve but is merely exacerbated by changes to the exhaust.
I would think that one repercussion of excessive popping is burning up the fiberglass packing of an aftermarket muffler more quickly.
To me motorcycles smell bad enough and my preference would be to preserve the PAIR valve rather than shaving off a couple of excess pounds. Unfortunately most aftermarket exhausts are "off-road/race" exhausts and do not allow for the preservation of the PAIR valve or cat. Where is the high-performance CARB-compliant full system? Call me a dork (really, feel free!) but I would like that.
To the points above the pair valve provides clean air to the exhaust. The heat and this O2 supply are enough to ignite the excess fuel in the exhaust. Note that this is always going on by design of the PAIR valve but is merely exacerbated by changes to the exhaust.
I would think that one repercussion of excessive popping is burning up the fiberglass packing of an aftermarket muffler more quickly.
To me motorcycles smell bad enough and my preference would be to preserve the PAIR valve rather than shaving off a couple of excess pounds. Unfortunately most aftermarket exhausts are "off-road/race" exhausts and do not allow for the preservation of the PAIR valve or cat. Where is the high-performance CARB-compliant full system? Call me a dork (really, feel free!) but I would like that.
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I have a Bazzaz Z-Fi system on my bike along with the O2 eliminator bike was dyno tuned and the AFR is good. I haven't blocked off the Pair yet.
I'd have to hook up my laptop to the Bazzaz to find out what my AFR is sometime but last time I did it was 12.8 which I'm told is good.
I'd have to hook up my laptop to the Bazzaz to find out what my AFR is sometime but last time I did it was 12.8 which I'm told is good.
Mythos
Registered
The AFR might change from fuel mapping, or changing the exhaust.
Unburnt combustion byproducts will ignite in the hot pipe when the outflow of exhausts stops at zero throttle. The PAIR allows additional air into the exhaust. The additional air ensures that the heat will ignite the combustion byproducts. If you put the PAIR back on your bike, it may start to pop when you engine brake at zero throttle. My 08 doesn't do it at all unless the exhaust gets really hot. No problem with popping when PAIR was in either. Removing the PAIR reduces weight of the bike. It is not possible to properly AFR tune the bike if the PAIR is working.
