Bouncing Idle

cobravenom39

Registered
Need some help.

Last week I did the pair valve mod. I did everyting by the book. I removed the valves (didn't scrape the old gaskets because they were in perfect shape) put some ultra black on them and bolted them on. I put a cap on the airbox and pluged everything back in.

I also changed the spark plugs, same as stock(gapped at .30).

I put everything back together hopefully the same as I took it apart.

Now the idle is bouncing around a bit.

It stays at 1100, then if I rev it, it will go down to 1700 than go back down to 1100 after a while. No rhyme or reason to it.

Any help appreciated.

Bike is performaning perfectly and feels just as powerful.
 
i'm no tech gugu but did you go back in and recheck everything as far as plug ins go? maybe one got loose?
 
No, you made changes to the induction circuit by removing the airbox, and the spark....by the way, I gap at .028 as they then will slowly wear towards the max limit. Just me, just the way I gap, no biggee....

I'd check your idle screw setting, and synch the throttles.....I believe one is breathing a wee bit more than the rest. This creates what I call the "giddy-up" idle.....doesn't want to settle down. It will eventually, but if the throttles are breathing even, and the idle is at 1150-1200, then it should just come back down without waiting. Also check that the vacuum to your flapper valve is connected....but it's probably in the idle setting, and the synch factor...also, did you plug that small 4mm hose that was the vacuum signal to the old pair valve ???.....second to last vacuum on the throttle on the rider's right :oldcool:
 
No, you made changes to the induction circuit by removing the airbox, and the spark....by the way, I gap at .028 as they then will slowly wear towards the max limit. Just me, just the way I gap, no biggee....

I'd check your idle screw setting, and synch the throttles.....I believe one is breathing a wee bit more than the rest. This creates what I call the "giddy-up" idle.....doesn't want to settle down. It will eventually, but if the throttles are breathing even, and the idle is at 1150-1200, then it should just come back down without waiting. Also check that the vacuum to your flapper valve is connected....but it's probably in the idle setting, and the synch factor...also, did you plug that small 4mm hose that was the vacuum signal to the old pair valve ???.....second to last vacuum on the throttle on the rider's right :oldcool:

Vacuum Signal to the old pair valve? I only plugged the large hose that goes to the pair valve.

I think for some reason I removed the vacuum assembly. Is it possilbe that I installed the vacuum sensor backwards?
 
also, did you plug that small 4mm hose that was the vacuum signal to the old pair valve ???.....second to last vacuum on the throttle on the rider's right :oldcool:


Ding Ding Ding

Winner!!

Thanks for your help Spudley!!

I pulled the line and capped and it's idling perfect, or as perfect as 1299cc's can idle.
 
Any pix for us visual guys? Please?

Yeah, I got the how too from Ward's web. Here's the link and the pic:

2000 Suzuki Hayabusa Modifications : PAIR Valve Removal

pair_cap.jpg
 
"HEY"...the Spud got a ding-ding-ding, which beats a doo-da-doo, or a yuht-uh any day !!!!

No, you can plug the airbox, and the vacuum signal as shown in the pic and leave the pair valve where it's at. No major performance advantage, but it gets rid of the popping, and back-firing on downshift.....

"One's glad to be of service".
 
Uh oh, I was out tonight and I noticed the bike's been doing the same thing. It will idle normal for a while, then when it gets over the half mark, it will idle to 1800 rpms, then when the fan kicks on, it will drop again. It's driving me nuts.

I haven't done a throttle body sync, and I plan on it, but it isn't related to that. I checked all the hoses. This guys also having or had the same problem
https://www.hayabusa.org/forum/busa-problems/96948-high-idle.html
 
Did you replug in the hose to the airbox flapper valve ???.....if so, then yes, synch throttles, set idle at 1150-1200, and it'll be fine.... :super:
 
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