rich.m

Hey everybody I've been apart of the forum for a year now ( just lurking in the shadows) and this well be my first post. First off thanks for all the info on the cct swap, just did mine worked out problem free.

I have been reading up on the PAIR removale ( figure i might as will get done what I can well Iam in there) and have a question mabe one of you can answer. Exhaust pipes produce preasure waves, Both negitive (sucking air out of cylinder=good) and positive (forcing exhaust gas back into cylinder=bad). When I first heard of the PAIR valve I thought this was a way of dealing with the positive wave (which also causes dubble carberation making mixture to rich). The freash air introduced by the PAIR valve would bring the mixture closer to normal.

Is there any truth to what I am saying or am I out to lunch? any input is welcome Thanks

VTRsurfer

The PAIR (pulse air) is strictly an exhaust emission control device. I induces fresh air into the exhaust stream to burn excess hydrocarbons (unburned gas) in the exhaust. It has absolutely no effect on performance, but some remove it to reduce weight (every ounce counts to some), or to eliminate deceleration backfire which sometimes occurs from the burn in the header pipes. Although an antibackfire function should prevent decel backfire.

It's function is the same as the old "smog pump" that was used on many cars from the late '60s through the '90s, except it eliminates the belt driven pump.

rich.m

thanks for the info man that clears it up a bit.

think I might just leave it on, I kinda like the backfire...gives character

steve29

If you ever plan on dyno tuning remove it. I had my hawk dyno tuned with it fully functional and the bike ran lean and would backfire thru the carbs. As was explained to me by 8541 hawk (who really knows his ****), you will never get the proper results on the dyno with pair functional. Why? Because as vtrsurfer said it injects air into the exhaust. Thus preventing the dyno tuner from getting an accurate fuel/air ratio. But, to each their own.

VTRsurfer

+1
Good point! When using an exhaust analyzer with the dyno, the air/fuel ratio will show leaner than it is due to being diluted by the PAIR.

nothing

thanks for this info guys, been wondering myself

rich.m

Thanks for the heads up on the dyno thing I'll keep that in mind

steve29

No problem. Learn from my mistakes. Haha