Inconsistent idle; either dies or revs to high

[glasnost79]

Well as the title says I am having problems with my 1983 GS550's idle. I just had the carburetor cleaned at a shop and put a new throttle cable on as well. I haven't ruled out an intake boot leak, but either than that I'm stumped. It idles progressively higher or lower and dies if I do not adjust the idle screw while riding it. I'm a learner, this is my first bike and although it is giving me problems at the moment I can really see why people like and respect the GS series. This is kind of my first post so go easy on me; a guy's gotta start somewheres.....

[Rock]

Have you had the carbs synchronized?

[Dave8338]

Well as the title says I am having problems with my 1983 GS550's idle. I just had the carburetor cleaned at a shop and put a new throttle cable on as well. I haven't ruled out an intake boot leak, but either than that I'm stumped. It idles progressively higher or lower and dies if I do not adjust the idle screw while riding it. I'm a learner, this is my first bike and although it is giving me problems at the moment I can really see why people like and respect the GS series. This is kind of my first post so go easy on me; a guy's gotta start somewheres.....

Welcome...Basscliff will be officially greeting you at some point. \\/

As for the bike, I hope you mis spoke and are not really making adjustments as you ride...I found out first hand, what fresh asphalt tastes like, by doing the same thing many years back. These bikes can be a little tricky to get set right as they tend to run lean. With that being said, pay particular attention to the boots, before and aft of the carbs. When no one is looking (reading) grab the starting fluid and give each boot/connection a little shot and see if the RPM's increase. If so you have found a leak. If you have not replaced the o-rings between the intake boots and the heads, do them first...they'll need it and it allows that area to be ruled out. Let us know what you find.

[chef1366]

Where in the central valley are you?

[glasnost79]

Welcome...Basscliff will be officially greeting you at some point. \\/

As for the bike, I hope you mis spoke and are not really making adjustments as you ride...I found out first hand, what fresh asphalt tastes like, by doing the same thing many years back. These bikes can be a little tricky to get set right as they tend to run lean. With that being said, pay particular attention to the boots, before and aft of the carbs. When no one is looking (reading) grab the starting fluid and give each boot/connection a little shot and see if the RPM's increase. If so you have found a leak. If you have not replaced the o-rings between the intake boots and the heads, do them first...they'll need it and it allows that area to be ruled out. Let us know what you find.

I know I shouldn't be adjusting as I ride, but stopping and going at 3-6 rpm's is also pretty dangerous....... and I don't want a hole in the engine.... I really have trying to avoid the inevitable, but I know it needs to be done, probably an entire carb rebuild..... I do suspect the intake boots to be faulty, but I bought this bike after it has been sitting for 8 years :? thank goodness for the resources here!!

[glasnost79]

Where in the central valley are you?

By modesto, I'm sure you've heard of it, how's the weather down south?

[moose09876]

I'm having almost the exact same issue. I've had the carbs apart and cleaned them 4 times, adjusted valve clearance, replaced o-rings, replaced spark plugs. I'm going crazy over this one. I'll rev it up to see where it will idle, and it usually stays between 2500 and 3500 rpm. If i try to adjust the idle screw, the idle usually drops to 1k rpm or lower and slowly dies. ANY help would be appreciated.

[Nessism]

I'm having almost the exact same issue. I've had the carbs apart and cleaned them 4 times, adjusted valve clearance, replaced o-rings, replaced spark plugs. I'm going crazy over this one. I'll rev it up to see where it will idle, and it usually stays between 2500 and 3500 rpm. If i try to adjust the idle screw, the idle usually drops to 1k rpm or lower and slowly dies. ANY help would be appreciated.

Sounds like a lean mixture at idle. Most common causes are 1) intake boot O-rings leaking (if your model bike has these), 2) pilot mixture screws are in too far.