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Unplug the PAIR system.

4991 Views 6 Replies 5 Participants Last post by  i64X
Hello everyone.

I installed a full exhaust in my R3 and now I want to eliminate the backfire.
Watching some videos on Youtube, I realized that we don't need to install a block off plate if we just disconnect and block the tubes and electrical wire of the PAIR system. So, I have a doubt:

If I only disconnect the electrical wire from the solenoid, will I have "turned off" the PAIR system? Or do I really need to disconnect and block the tubes too?
Can someone help with this information?

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Havent tried this on my R3, but did on a different bike. I am sure its the same for most bikes.

If you dont plug/block off the hoses, you allow air to return to the system. This leads to popping and will be more obvious with an aftermarket exhaust.

When you unplug the valve, you need to trick the bike into thinking it is still plugged in, otherwise you get an engine light. You do this with a resistor, or just leave the old valve plugged in but not connected. If you race and think "ounces = pounds" then sure take it off and add a resistor. The only advice I have if you go with a resistor is to properly weather proof it. Mine was fine for a while, and when the rains came (San Diego doesnt rain that much), it was enough to burn my resistor.

I cannot comment on how the O2 sensor acts with this, as my previous bike did not have one, but maybe this thread will help:


If you are cheap (like me) you can block off hoses/air box with plugs you can get at the auto store, or use marbles. Yes, marbles.
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There's no light on the dash if you unplug the solenoid. However I don't know if the default position of the solenoid is open or closed. I'd say unplug it and then remove and cap off both ends of the hose from the airbox to the solenoid.
If your already in there just install a block off plate and cap off the air box. That's just my opion just seems easier & simplified. When I did my install of the Dyno-jet PCV and block off plate. Install video just says to unplug solenoid and tape off well with electrical tape. On the oxygen sensor it has been rendered useless. As I installed the provided oxygen enhancer from Dyno-jet that came with my PCV. (Auto-tune comes with a sensor)

1st day installed full Yoshimura R77 exhaust and took it for a ride. popped on the let off and take off upshifting.
2nd day Installed block off plate and capped air box. Installed PCV and oxygen enhancer. Took it for a ride and tried to get it to pop on the downshift and let off. Not happening anymore. There's still a hint of a crackle once and a while when I let it rip.I can't tell you what fixed the popping as I installed the PCV and block off at the same time.

I have not done a thing since and the bike runs great I do have the db killer installed in my pipe.
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sorry love posting this photo.

Here the full exhaust and pre programmed PCV from Hardracing.com
Last night I have unplugged the solenoid wire and blocked off the tube from the air box to the solenoid. I just removed 1 piece of fairing. I had some job, but worked fine. The popping have reduced about 70%.

It s clear how yamaha (and I think all other brands) tunes up their bikes to work poor of fuel. My stock exhaust has about 800km and not a single signal of black powder inside it. Even in the aftermarket one.

My stock exhaust had some popping too. I'll have to install a PCV soon.
The block off plates aren't necessary. You can pull the hose off of the stock plate and then just put a vacuum cap over it the same way the block-off plate kits typically have you do it with the airbox.

I've done this on a ton of bikes and I've never had a check engine light come on, nor have I had any adverse effects. It helped the exhaust popping on my FZ1 100% with a shorty Yoshi pipe on it. Vacuum caps are typically cents at a hardware or automotive store.
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