idle hanging up around 2500 RPM gs1100E

[Guest]

I just received my carbs back from a professional overhaul and installed them on my stock 1980 GS1100E. I sent the carbs out because they were stumblimg a bit coming off Idle. I am running Stock jetting, stock air box and stock exhaust. The carbs look incredible nowand seem to have been done very well! I installed them on my bike and all seemed wonderful as I rode off smoothly and powerfully. However when I backed off the throttle the RPMs hang up at about 2500 RPM for about 10 15 seconds (sometimes longer) then idle drops down to a normal 1200 idle. I made sure I had lots of free play in my cables and even pushed the linkage doewn by hand but the idle seems to be hanging up even when the throttle is completely closed. When it hangs up I can drop it down by using the idle screw but then it drops below 1000 and stalls when the 10-15 second time goes by. SO, I put a spare set of carbs on it and guess what?! Same thing. That makes me believe something is going on besides the carbs but I am baffled at what would cause this phenomenon. I sprayed the intake boots looking for a vacumm leak but no leaks. I feel like Im crazy, but thats what the bike is doing; makes no sense to me. Any thoughts would be appreciated.

[tom203]

Did you or your professional bench sync this rack before installing? How sbout the idle/air mixture screw setting?
Clamps tight on those carb hose gizmos?

[eil]

Were the carbs rebuilt by a forum member? (You don't have to name them if you don't want to, but if you went with a local third-party, they probably didn't clean the carbs correctly.)

Even if the carbs were built correctly, a bench sync only gets you so far.

I'm not saying it will totally solve your issue, but you do need a proper vacuum sync with the carbs on the bike to get them dialed in on the low end. Plus adjusting the idle mixture screws like tom said.