Pair Block-off Causing Rough Idle

So while I was servicing the K&N filter on the bike the other weekend I decided to block off the PAIR valve as well as unhook the flapper valve on the airbox. For the PAIR valve I took off the hose on the LH side of the airbox (on the back, the one that leads to something that looks like a valve, I think) , plugged it, then re-attached it to the airbox. For the flapper valve I simply on-hooked the vacuum line from the solenoid on top of the airbox and plugged it with a golf tee.

I only got around to riding it yesterday and noticed the idle was horrible (low, wandering, put-putty) and the bike was hard to start. There also seems to be a good bit of vibration coming up through the tank while riding. Aside from that, the bike runs great. The low-end surging/bucking has all but disappeared.

I re-attached the vacuum hose for the flapper valve but left the PAIR hose blocked. The idle improved but isn't back to normal. The vibrations are still there as well.

Did I do something wrong, or does the PAIR block-off 'mod' require me to do something else, like possibly raising the idle?

If it DOES require raising the idle, I have another question. I BELIEVE I know where the idle knob is (black knob about the diameter of a dime on the RH side near the engine case). I have tried to mess with this before, but it seems like the thing just doesn not want to turn. I'm hesitant to crank on it because I've broken quite a few things in my lifetime by being rough with them. Is there some technique that I am missing?

Mike

PS - total powertrain 'mods' are K&N, snorkel removal, and 2 Bros exhaust (slip-on).

just turn the knob and mine is really difficult.i use a phillips head screw driver to turn mine so i dont burn myself.

[image: View Post]whiteboyslo, on Aug 5 2009, 10:58 AM, said:

Did I do something wrong, or does the PAIR block-off 'mod' require me to do something else, like possibly raising the idle?
Yes, the idle needs to be adjusted up by about 300 rpm.
I've disabled the PAIR valves 3 times, and each time put it back after a day's riding, as it always seems to run worse. So much for those who say ti has no effect on engine performance as it's downstream of combustion....

[image: View Post]enzed_viffer, on Aug 5 2009, 09:26 AM, said:

[image: View Post]whiteboyslo, on Aug 5 2009, 10:58 AM, said:

Did I do something wrong, or does the PAIR block-off 'mod' require me to do something else, like possibly raising the idle?
Yes, the idle needs to be adjusted up by about 300 rpm.
I've disabled the PAIR valves 3 times, and each time put it back after a day's riding, as it always seems to run worse. So much for those who say ti has no effect on engine performance as it's downstream of combustion....


I agree.

Disabling the PAIR makes the idle richer somehow, my PC3 map is leaned off at 0% throttle and around 1500RPM.
My personal theory is some air sneaks back past the exhaust valves during the overlap phase at idle, and when the air supply is removed, the result is a richer mixture and slower idle.
Anyone got a better idea?

did you also detach the wires to the solenoid thingy when you blocked the PAIR hose?

The entire purpose of the pair system is to burn unburned fuel in the exaust headers for emmissions purposes, when it does this it tends to draw out exhaust from the cylinders increasing idle sort of a ram jet effect. However it also strangles off intake air at full thottle which is why people remove it, it robs horsepower at top end.

[image: View Post]AB-Oz, on Aug 4 2009, 08:22 PM, said:

did you also detach the wires to the solenoid thingy when you blocked the PAIR hose?

uhm, no. that might explain the intermittent buzziness.

OK, so up the idle and unplug the wires on the valve. got it.

Mike

a-ha! yeah, using the screwdriver on the idle knob is a must. bike is running fantastically now. i also unplugged the harness. the damn thing was stuck and took a lot of convincing but i got it without destroying it.

Mike

[image: View Post]whiteboyslo, on Aug 7 2009, 08:28 PM, said:

a-ha! yeah, using the screwdriver on the idle knob is a must. bike is running fantastically now. i also unplugged the harness. the damn thing was stuck and took a lot of convincing but i got it without destroying it.

MikeI ended up cutting the selinoid wires to remove it. I don't like dissassembling a lot of stuff.

What's the long term effect of this on the catalytic converter? Will it eventually plug up with carbon due to the increase of unburned fuel in the exhaust?

Back a few years ago, Formula Extreme was getting protests about the pair system being removed. After extensive testing they stopped hearing protests about this because they determined there was absolutely no horsepower increase. This comes from the head tech inspector at the time.

I think the difference in idle is the vacuum difference because you have changed one parameter of the whole intake system.

[image: View Post]whiteboyslo, on Aug 4 2009, 06:58 PM, said:

So while I was servicing the K&N filter on the bike the other weekend I decided to block off the PAIR valve as well as unhook the flapper valve on the airbox. For the PAIR valve I took off the hose on the LH side of the airbox (on the back, the one that leads to something that looks like a valve, I think) , plugged it, then re-attached it to the airbox. For the flapper valve I simply on-hooked the vacuum line from the solenoid on top of the airbox and plugged it with a golf tee.

I only got around to riding it yesterday and noticed the idle was horrible (low, wandering, put-putty) and the bike was hard to start. There also seems to be a good bit of vibration coming up through the tank while riding. Aside from that, the bike runs great. The low-end surging/bucking has all but disappeared.

I re-attached the vacuum hose for the flapper valve but left the PAIR hose blocked. The idle improved but isn't back to normal. The vibrations are still there as well.

Did I do something wrong, or does the PAIR block-off 'mod' require me to do something else, like possibly raising the idle?

If it DOES require raising the idle, I have another question. I BELIEVE I know where the idle knob is (black knob about the diameter of a dime on the RH side near the engine case). I have tried to mess with this before, but it seems like the thing just doesn not want to turn. I'm hesitant to crank on it because I've broken quite a few things in my lifetime by being rough with them. Is there some technique that I am missing?

Mike

PS - total powertrain 'mods' are K&N, snorkel removal, and 2 Bros exhaust (slip-on).


Mike,

When doing the pair valve block, you will allways need to speed the tick over up, incidentally there is a very easy way to do this, as follows:
Remove the screw that holds the fairing on nearest to the black adjuster knob (tick over adjuster) reach in with your finger and lift the black knob out of the bracket that holds it onto the frame, you will then find that the knob turns very easy.

Plasma