'89 FJ1200 idle speed jumpy after carb clean, rebuild & sync...

[coreyoreo]

Hi, all,

Just had my carbs cleaned, rebuilt & synched by a local bike shop. (I don't have the experience yet to do this myself) Anyway, when I was leaving the repair shop, the idle speed suddenly went to about 2500rpm, so I went right back & they looked at it (while I was watching) & re-adjusted the air-fuel & the like, got it to idle steady about 11-1200rpm, twisted the throttle a few times to make sure it didn't stick, & all was fine again.

  The next day, I started it up & the idle was very rough, about 7-800 maybe. Even after a short ride around town. So I fiddled w/ the idle adjustment screw a few times & just cound not get a happy medium idle speed-- it was either 2500rpm or, after a few turns of the idle screw, back down to 7-800rpm. Throttle cables appear to be operating ok otherwise, but not totally sure on that.

Any ideas what could cause this? Something must be sticking... I don't wanna take it back to the shop if I don't have to...

Thanks for any help.
Corey

Note: this is a bike that was sitting for a couple years, so that may have an impact on how it idles, but since the carbs been cleaned & rebuilt, I don't know why I can't get an even idle speed.

[racerman_27410]

does the idle change when you turn the bars from left to right fully ?

it could be the throttle cables binding.


KOokaloo!

[coreyoreo]

No I have not checked that yet racerman, feel silly I didn't think of that, but I will check today when I get home from work & report back.

Thanks for the idea.

[markmartin]

I had a similar idling issue after syncing my carbs (and playing with the idle speed)  a few weeks ago.  Tightening the rubber boots around the carbs helped.  It took a lot of frigging around with the idle adjustment, but I finally got it to idle consistantly at 1000 -1100 when fully warm, and it's running very well otherwise.  When I get to servicing my carbs, I'm going to change all rubber boots, o-rings, and caps possible. It could be a number of things, but I've got a sneaking suspicion old rubber is at least part of my problem.

[Dan Filetti]

I had a similar idling issue after syncing my carbs (and playing with the idle speed)  a few weeks ago.  Tightening the rubber boots around the carbs helped.  It took a lot of frigging around with the idle adjustment, but I finally got it to idle consistantly at 1000 -1100 when fully warm, and it's running very well otherwise.  When I get to servicing my carbs, I'm going to change all rubber boots, o-rings, and caps possible. It could be a number of things, but I've got a sneaking suspicion old rubber is at least part of my problem.

+1, happened to me on another bike as well.  Spray some starting fluid in and around the intake boots while the bike is running if the idle increases, you have an intake leak.

Dan

[coreyoreo]

I had a similar idling issue after syncing my carbs (and playing with the idle speed)  a few weeks ago.  Tightening the rubber boots around the carbs helped.  It took a lot of frigging around with the idle adjustment, but I finally got it to idle consistantly at 1000 -1100 when fully warm, and it's running very well otherwise.  When I get to servicing my carbs, I'm going to change all rubber boots, o-rings, and caps possible. It could be a number of things, but I've got a sneaking suspicion old rubber is at least part of my problem.

+1, happened to me on another bike as well.  Spray some starting fluid in and around the intake boots while the bike is running if the idle increases, you have an intake leak.

Dan

Thanks Dan & Mark, I'll try the starting fluid method..

I understand about tightening the rubber around the ports... But O-rings & caps.. can you please elaborate?

[markmartin]

I understand about tightening the rubber around the ports... But O-rings & caps.. can you please elaborate?

Go to this link for the o-rings http://www.rpmracingca.com/proddetail.asp?prod=carbkit&cat=39

Note the intake manifold o'rings.


The caps I'm referring are the ones that cover the stems that the syncronizer tubes are hooked to when syncronizing the carbs.

[coreyoreo]

Ok, great info. I don't recall seeing any intake o-rings when I removed the carbs for cleaning, so that's probably one issue.

The caps I'll look into, also.

Thanks for some great ideas!!

[markmartin]

Ok, great info. I don't recall seeing any intake o-rings when I removed the carbs for cleaning, so that's probably one issue.

The caps I'll look into, also.

>snip<

Well coreyoreo, I havn't even taken the carbs off my bike yet, so i'm assuming that these intake o'rings should be there.  Something I'll be looking for when I do service them.  


Does anyone know if the rubber caps that cover the stems that are used to sync the carbs are available?  I didn't see them listed on Randy's site but maybe I don't know what I'm looking at??


Thanks

Mark

[oldktmdude]

   The o-rings are located between the head and the intake boots, not between the carbs and intake boots so you would not have seen them by just taking your carbs off.  Pete.

[Yamifj1200]

"Does anyone know if the rubber caps that cover the stems that are used to sync the carbs are available?  I didn't see them listed on Randy's site but maybe I don't know what I'm looking at?? "


Your local auto parts store should have vacuum caps... I found a set of them in differant sizes at Advance auto.
http://tinyurl.com/3e7e6gv

Hope this helps...

Eric M