I have a '93 GS that I am trying to get back on the street after many years of sitting in a garage. I have cleaned up the carbs and replaced all the gaskets and o-rings. Now I am having trouble getting it to run right.
What it does:
Starts fine with choke. Stumbles if I give it more than gradual throttle. Once warm, turning off choke it settles to about the right RPM (don't know exactly as it doesn't currently have a tach). Still have to give very gradual throttle. Once it does spin up it hangs at 4-5k RPM (again, a guess based on what it sounds like). If I put my hand over the air intake, it spins even faster. If I hold my hand there it will eventually die.
What I have checked:
All carb passages are clear. All gaskets/o-rings are in place. No apparent air leaks. Float levels look fine. Started with air screws about 2.75 turns out (where they were when I took it apart), but have adjusted them a couple turns either direction while it was running with no apparent effect.
Any suggestions what to try? I am stuck and rather frustrated.
I hope its not the same gas in the tank thats been sitting for years?
Hah! No. Not even the same gas tank.
Sounds like the little Ports on the pilot circuit are clogged. There are 4 or 5 of them under the throttle valve. The ones behind the throttle plate are used to richen the mixture when you open the throttle. If those are clogged you will have a severe stumble or stall when you go to open the throttle. Its probably time to pull out the carbs, disassemble them, and clean the works.
Make sure you check all the orings and replace them if needed.
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+1.....pull the carbs again...this time remove all the rubber parts and dip them in a carb dip overnight.
Have pulled them multiple times. As far as I can tell all the passages are clear. I have worked on GS's for years and never had one this irritating.
If you are sure that everything is clear then you can try adding more shims to the needle to make the mid range richer. But if nothing else changed them something happened to change your mid range. Could be a minor vacuum leak or exhaust leak. Either way your mid range is lean from what you describe.
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