|
The PAIR system is part of the Emissions Control set
up, adding air to the exhaust gases at certain times to 'clean up'
un-burnt fuel. A side effect of the process, that becomes more
noticeable with aftermarket cans, is exhaust 'lean popping' or even
mild backfires. (tell me more)
Airbox removal
Chewy's PAIR removal kit By
Bjam 06/2003 Here are a series of pictures
showing the PAIR system designed to 'inject' air into the exhaust
manifold to clean up the emissions and promote a cleaner burn.
First picture is an overview of the system with the tank and
air-filter taken off. Number 1 is the solenoid where you can see an
open pipe that is normally connected to the airbox and the
electrical connector nearby. Number two is where the air pipe
connects to the rear cylinder head via a plastic manifold (more
pictures of this below). There is also a pipe running to the front
cylinder connected to an identical manifold that is obscured by the
frame.
This is a picture of the system removed from the bike.
1. This is the electrical connector to the bike.
2. This is the pipe that normally attaches to the airbox and acts as
a feed for the system.
3. This is the disconnected pipe that was fitted to the rear
cylinder.
4. This is where the pipe for the front cylinder feed is normally
connected.
5. This is the PAIR solenoid.
Below is the manifold removed from the rear cylinder and the second
photo is where the manifold attaches to the cylinder head. The
finger points to the hole where the air is ingested. One thing to
note was that this chamber was very sooty..
1. This is the air input where the pipe connects.
2. Just below the number two is a curved metal strip the must act as
a one way valve to stop reverse airflow.
And finally, here is the solonoid taken apart.
1. This is the main body of the solonoid with connector. This is
simply a coil that, when energised, will magnetically operate a
plunger to allow air into the system.
2. This is the air input tube and manifold - very simple as you can
see
3. This is the plunger that sits inside the solonoid.
4. This is the bottom of the mechanism and simply serves as a two
way manifold for letting the air into the pipes leading to the
exhaust. In other posts this is where it has been suggested to
introduce a ball-bearing to stop air flow.
It would appear that the PAIR system is very basic and, instead of
injecting air into the exhaust, it simply has a plunger, operated by
a solenoid, that either lets air into the pipe work or not. I ran
the bike with the system disconnected and there were no problems
with the FI detecting that it wasn't there. There are one of two
things that could be done:
1. Place the ball-bearing or obstruction into the disconnected pipe
that normally attaches to the airbox. This would prevent any air
getting into the system and saves having to do the same thing twice
at the cylinder heads.
2. Junk the system altogether and save 500 grams (.5 kilo) in
weight. The inlet manifolds on each cylinder head would need to be
blocked off though to prevent a constant source of air. Comments
Jimbo77
That "magnetically operated plunger" is where the "ticking" noise
comes from...
......Those are some mighty informative instructions. I'm surprised
there is no problem from disconnecting the PAIR system completely. I
would have expected it is controlled by the ECU, thus a warning
indicator if something is amiss.
Bjam
I too was surprised that the bike started and worked fine with the
system disconnected. In hindsight, being a simple solenoid with an
either on or off action, perhaps the FI doesn't really need to know
it is getting on with its job. The clever part is the FI pulsing the
on/off signals at the right time to reduce emissions.
Glad you pointed out the ticking noise, that makes a lot of sense
now.
nittyp Is there no way to block
the PAIR valve without taking that whole thing out?
TLRMan
The quick fix would be to block off the hose #2 . Either with ball
bearing Like Jim had posted earlier. You could take a bolt, and
screw it into the hole that the tube plugs into, from the airbox
side.
I don't see why we couldn't make up some plates to cover up where
the original piece bolted onto the head. Use some permatex hi temp
RTV, and call it a day!
If you try to block off the tube at the heads, it would just blow it
out. NB: Update on that:
The manifold device that bolts onto the head has the reed valve
incorporated into it...So all you have to do is just cut the hose
short and plug it there on both cylinders...you then can remove the
rest of the system. On the earlier TLR/S the reed valve assembly was
up stream before it split into 2 pipes, and then when down to the
outside of the head.
If you tried to block them off after the reed valve, the exhaust
pressure would blow the tubes off.
This is a newer design which feeds in from the top, and the read
valve is part of the plastic manifold.
I figured just to make it look better, and having the plastic
manifold sticking out with a hose and a ball bearing, or bolt stuck
into it it would look more professional with just a cover machined
up, and placed over the hole where the plastic manifold used to go.
RTV is Room Temperature Vulcanizing...sealer. Also know as silicone
sealer.
It cures into a rubber gasket, commonly used when assembling parts
that have no gasket. The crankcase halves use this, to seal it.
Using a high heat rated type won't allow itself to deteriorate with
heat.
.....You won't see any performance gains at all except
loosing some weight if you remove the system, and block off the
holes.
What it does do, is eliminate the backfiring on decel which is
common if you install aftermarket pipes/cans.
It also defeats the cleaner emissions from the exhaust. Oooooops!
One note to all, is if you do go on the Dyno, and do some tweeking
with a PCIII or comparable device, you would want to disable it, so
the Exhaust gasses you are reading are true. The Pair valve will
make you think it's leaner than it is.
Flange
...you make the very good point that an active PAIR system would
introduce falsing into an exhaust gas analysis.
Do you think that simply unhooking the PAIR electrical connector
would suffice when sampling exhaust gas, or would a sufficient
quantity of residual atmosphere be sucked from an electrically
disconnected PAIR system to significantly affect the EGA readings ?
TLRMan
I would expect it all depends on how good the solenoid and valve
seal at the feeder tube side. Best bet would be to just plug it up
from the airbox, and do the Dyno pulls...This would ensure no false
A/F readings. We know it's open on decel, but may open during accel
too. should meter it, (the solenoid) and find out when it does.
pdoyle64
I blocked the pair valve with a 3/8" bolt tonight. It threaded right
into the opening in the airbox. I safety wired it and used a little
silicone so it won't back out. No more popping on decel. Cool!
drmudd
I connected the two hoses from the cylinder heads together. Then
removed the intake tube, plugged hole in air box, and mechanical
part of the solenoid leaving the magnet with its wire in place.
Plugged air box from the underside so as not to worry about objects
being sucked in.
Learn more about the PAIR valve:
www.volusiaowners.com and
www.moccsplace.com
Top |
