Hi all,

Looking thru some forum I see some people have delete their PAIR system but I'm not seeing anything about the solenoid valve. Just got this bike and the PAIR system is still there but the solenoid valve is gone and it's tubing. The PO ran the 2ndary air tubes from the top of the carbs (red) to the bottom of the PAIR valve and removed the long (green) tube from the bottom of the PAIR valve that runs around the left side of the carbs to the bottom backside of the air box so that port is blocked off now. So other than that bottom tube redirect, the PAIR system is all connected and the crankcase breather hose (blue) is still there to attach to the bottom frontside of the air box.

Anyone know if this redirection of the bottom PAIR valve tube into the carbs is the correct way to delete the solenoid valve? Is deleting the solenoid valve even a thing?


from another forum


my depiction of what is going on with my F4


my F4

Thanks in advanced for any input!

 

Previous Owner is an idiot! There are 3 completely independent systems involved:

1. PAIR injects extra air into exhaust to further complete combustion and lowers HC emissions. The PAIR valve is powered by vacuum to pump air from air supply hose into exhaust through the reed-valves on top of head.

2. EVAP / DAI deals with petrol fumes. It stores evaporated fumes from tank during hot days into canister. Then these fumes are vented back to carbs by EVAP purge control valve along with air vent control solenoid valve, CAV solenoid valve at various operating ranges.

PAIR and EVAP doesn't affect operation of engine or its power-output in anyway. So there's no benefit to disabling them. Only benefit comes through weight-savings in removing everything. PO's attempt at disabling both just compromises proper carb-operation by interfering with the DAI system. The PAIR valve will suck air out of carbs instead of airbox and will cause all issues with proper fueling. What you call 2ndary air tubes are actually float-bowl air-vents to provide atmospheric pressure reference. With PAIR sucking on those, it would raise float-levels and throw off your AFR.


What you can do at moment is:

- restore PAIR operation, re-connect air supply hose to airbox and PAIR valve inlet
- connect float chamber air vent hoses to airbox

This may not work properly until you get air vent control solenoid valve and reconnect hoses properly. The valve changes pressure in float-bowls depending upon state of ram-air tubes to account for extra air-flow

 

Hey dannoxyz, thanks for the reply and helping me understand what these systems are actually meant to do. That's crazy what they hooked up together. I will get these opened up to fresh air as you described.

Seriously, thanks!

PS. I don't have a tube that goes down by the rear shock, but I'm guessing that's supposed to be a drain tube or something? Maybe something else isn't being vented properly either? Everything else I was able to pinpoint and attach properly based on the manual diagrams.

 

Sorry, got mixed up with previous models without ram-air. Those didn't need to vary pressure in float-bowls. So vented to atmosphere full time. Long hose is to prevent
contamination. I tried leaving hoses off one time and ended DNF at season-opening race at Buttonwillow because my engine died 1.5 laps in...

 

Is that a bug?? Got all the way into your jet, that must have been a real bummer.

I looked at some other threads for different models and it looks like I can just get rid of the the PAIR system entirely and keep the AVC solenoid valve off. The PAIR just burns extra fuel in the exhaust and the solenoid just switches to the ram air above like 12mph which is pretty much just at idle. So instead of buying an AVC solenoid and all the tubing, I'm just going to delete them all. But I need to make sure I plug/vent everything properly afterwards..

To delete the PAIR, it looks like I need to T the 3 crankcase hoses together (hydro-lock) and then plug the small hose that T's into the carb vacuum line?

Then just vent the red tubes coming off the top of the carbs down out of the way? And plug all of the air box holes that aren't being used anymore.

Let me know if anyone has any other suggestions. Thanks!

 

the only suggestion I have is to put it back in the bike. it may seem like an unnecessary system, but there really isnt a good reason to remove it either. it is a finely tuned piece of japanese machinery after all, and I have seen these modifications lead to running issues.

 

I definitely agree that the Japanese engineering on these bikes is finely tuned, but since I'd have to buy a used solenoid that hopefully works and all of the tubing I'm trying to see if I can make it run without it. I decided to leave the PAIR valve installed and just re-route the bottom tube (green) to the back-left of the air box (AB) as it should be. Then for the small carb line (red) that was coupled into the bottom of the PAIR valve, I can bypass the solenoid and hook it directly into the front left of the air box (AB) which is where the solenoid would have gone to.