Finicky Idle - please help

[buzzkill]

I've an '83 GS1100. Uni air pods instead of an air box on the carbs. Everything was fine until the bike was caught in a terrible dust storm. Afterwards, I was in a rush to get it out of the desert, so I rode it ten miles back to town. It stalled a few times, was hard to start. I took the air pods off and dust literally poured out.

I washed the pods very well and did a cursory cleaning of the carbs (everything you can see without taking off the top; did not take any jets out, just sprayed them where they were). After warming her up, the idle rpm would slowly drop until it stalled. When I raised the idle rpm (with the screw on the underside of the carb) to the point that the rpm would not drop, I would ride the bike for a while, then the idle rpm would stay really high when I released the throttle. Also, if I started the bike cold with this idle setting, after she warmed up, the idle would seem okay at the beginning, then slowly rise until it seemed much too high (forgive me, my tach cable is busted).

I checked the piston compression: three read 120psi, one read 100psi. That seems okay to me.

I did a more thorough cleaning of the carbs (admittedly not as thorough as Bikecliff's) and checked the petcock, which was fine. Still, the problem persists.

Can someone point me in the right direction on this, please? Thanks.


-buzz

[Nessism]

I did a more thorough cleaning of the carbs (admittedly not as thorough as Bikecliff's) and checked the petcock, which was fine. Still, the problem persists.

Can someone point me in the right direction on this, please? Thanks.


-buzz

You answered your own question.

[Buster-boy]

Clean them really good like Bikecliff said. The tiniest particle can get stuck in your jet(s) and really louse things up. Then have them synch'd. Should be good to go after that.

[cyclefvr2]

the compression difference is enough to make it run different, because there is a good amount of loss, also
use high octain fuel ,and try it you will be amazed at how much better they will idle with good fuel, thats all good fuel
set the air screws , the wore cyl will need re set to keep up with the others

[KEITH KRAUSE]

One of the classic symptoms of intake leaking is this ritual...
The bike idles at something close to factory rpm (1,000/1,100) after you close the choke and it's semi-warm. As it reaches full warm up, the rpm's keep rising several hundered rpm plus. You then turn down the idle to the factory idle by using the idle adjuster. It idles fine. You then shut it off and it cools. Next time you start it you need to turn up the idle or it keeps stalling while warming up. Once warmed up the rpm's again are too high. On and on.
Your description sounds like a possible leak but I can't be sure without riding the bike myself. What seems likely is dust got in since I assume there was no problem before the dust storm? Dust shouldn't "pour" out of the filters as you said. The Uni's should be oiled to catch the dust, unless you were just buried and the oil couldn't absorb it all. Almost certainly the carbs have grit in them. The pilot circuit has many small passages that are easily clogged. Depending on what gets clogged, you could experience fuel starvation/lean conditions and/or rich conditions.
You'll have to service the carbs. Then clean/oil the filters. Foam filters aren't that good. Just my opinion.