Any minuses to deleting the PAIR valve?

I figure while I have the bike pulled apart I would delete the pair valve.  Any reason to keep it after stage one mods?  I have very minimal decel popping. 


Any downsides to bypassing the kickstand switch as well?

The only downside of bypassing the kickstand I see is if you forget lift it up and you take off down the road

The only downside to deleting the pair valve is slightly higher exhaust emissions.

The only downside to deleting the pair valve is slightly higher exhaust emissions.

And what's the upside?

And what's the upside?


If you're using an AFR+ or a Bazzaz Autotuner you have to delete the pair to get correct O2 sensor reading on your wideband O2. However, so guy delete it on bigger bikes so that if they tune often the AFR valves will be correct at the dyno. It doesn't save a huge amount of weight... 

deleting it also eliminates or greatly reduces popping in the exhaust in high rpm chop throttle situations like coasting down, that is common with straight through aftermarket exhaust systems.

it is minor on fuel injected bikes like the CRF250L due to the fuel being shut off when the throttle is closed above 3500rpm but if you listen closely you will often hear a little pop when coasting and you open the throttle.


Kawasaki used a pair system set up just like this bike where the air is drawn in through a reed valve in the cam cover and passes through a port in the head next to the spark plug. on the kawasaki over time the gasket fails and they will start sucking oil into the pair port from the top of the head.


if your LRP starts smoking, you will want to inspect for oil in the exhaust port first before starting a over haul job. you may just need a cam cover gasket.


I have sealed the ports in my ZRX11. 

If you're using an AFR+ or a Bazzaz Autotuner you have to delete the pair to get correct O2 sensor reading on your wideband O2. However, so guy delete it on bigger bikes so that if they tune often the AFR valves will be correct at the dyno. It doesn't save a huge amount of weight...

An afr+ is a piggyback system to run with the ejk, correct?

An afr+ is a piggyback system to run with the ejk, correct?


the AFR+ is a self tuning EJK the most common EJK used on these bikes is a Dobeck performance generation 3 device and the AFR+ is a Dobeck generation 4 device. it uses a Bosch wide band O2 sensor and chip to automatically adjust added or removed fuel to air fuel ratios you set for it to adjust to. the regular EJK just adds what you set it to. it has no way to know or show you what is going on. the AFR+ has a ratio gauge so you can see what it is doing.


the one down side to the AFR+ (over cost) is there is not currently a good way to bypass the stock narrow band Honda O2 sensor and under certain throttle conditions the stock ECM and the AFR+ can get into a fight over what to do and that triggers a ecm reset and you feel that as a hick up. it can be adjusted to pretty much eliminate the hick up though.

Ok thanks for clearing that with me, so with a gen 3 there is not really a need to have the pair valve removed?

not really, you may get some popping on off throttle or opening the throttle but it will be minor compared to on a bike with carburator. the pair valve lets air into the exhaust stream for more complete burning (cleaner air) so with the pair exhaust system temps could be a bit higher.


its the feed back system fuel controllers that require you to disable it. without them you don't need to disable it.

Are there instructions on how to disable the pair valve somewhere?

I just got the AFR+ installed and haven't even ridden it yet. I noticed that once it warmed up, the AFR was showing a 15.5 :1 air fuel mix at idle.

Locate hose going into top of valve cover, remove hose from valve cover and install cap over port on valve cover.

Trace line to solenoid and remove there and cap port on solenoid.

You might be able to just unplug the solo pod but it might set a fault in the ECM.

Hmm that's quite lean for idle, mine idles on the rich side.

I was surprised as when I started it, it ran about 12.5:1. I thought, OK, it is cold. After it ran for a few minutes, the gauge sat at 15.5:1

Any idea what size the caps are?

I was surprised as when I started it, it ran about 12.5:1. I thought, OK, it is cold. After it ran for a few minutes, the gauge sat at 15.5:1

Any idea what size the caps are?


yeesh! I cant remember, I had picked up one of those generic assortments from the auto parts place, it was cheep enough and had enough to do the job.

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