I have a 05 gs500 f.
Before this project the bike had almost no power and the idle would stick at 5000 till given some drag then it would return to a rough idle. First tried adjusting mix screws and idle screw, no help. Noticed that the left side wasn't even firing.
I cleaned and inspected the carbs, could not find anything wrong. After checking and replacing with correct valve shims both problems stayed. Swapped coils and plugs made no difference. Checked compression on both sides, the right was bad the left was worse. Did a teardown and replaced: exhaust valves(and seals), piston rings and oil rings(lightly honed cylinders), seals between crank case - cylinders - head - valve cover, oil and filter. Measured and replaced shims again. The compression is now where it should be but still ran on one side and high idle. Inspected and tested wiring to the best of my knowledge. Disassembled carbs a second time and noticed the left pin in the intake was missing and the black slide would barely move (didn't remember it being that way before). After taking the tops off of the carbs (which i had not done the first time) I found the pin sitting with the diaphragm and the diaphragm undamaged. I copied the good side and re assembled it. I finally have both sides running now (as per the burn on my glove/finger). The idle is still bad. Couldn't find any damaged rubber(hoses and caps) or vacuum leaks(propane near engin dint change idle). Played with mix screws with no luck.
Mix screws are 3 turns out, idle screw is almost not touching, and when plug wires are pulled while running both sides seem to be doing the same amount of work. HELP!!

https://www.youtube.com/watch?v=xwfTo4axjeg

here is the link to a video of the current state with a warm engine.

stuck choke

The pins on both carbs move in and out with the choke lever. Unless there is another way to check this it seems not to be the problem.

Have you checked the throttle cables for stickiness?

Regards.

You could have no problems with any of it, and still have a high idle. Its setup lean from the factory, and some bikes are leaner than others. I'd eliminate all the other problems ... vacuum leaks, exhaust leaks, etc etc etc and finally if all else check out - rejet it to +1 ... its all stock ? then yea +1.

Cool.
Buddha.

Adidasguy had a thread awhile back about an elusive hanging idle.  He had a plethora of parts (Ultimate GS500 Bike Cave), so it was simple to continue swapping out known good parts.  Tried every suggestion anyone would think of that would cause a high idle - from swapping known good carbs and boots, to checking for and later swapping heads for a gasket leak, and every little bit in between such as cables and hoses... and before swapping parts, they did check over with typical troubleshooting methods, but since it was still there after those checks and adjustments - they went ahead and swapped with known good stuff.  When opening up the engine for a final attack at the issue, they finally noticed the timing was off by ONE tooth even after having checked this at least once before, if not twice if I recall correctly.  Never had heard of that causing a high idle before... but once that was corrected, the bike idled perfectly. It remained a mystery, however; how it had ever gotten off by a tooth in the first place

- Bboy

Was the hanging idle the only symptom if its timing was out by a tooth ?
I'll bet not. 1 tooth is huge.
Cool.
Buddha.

Honestly, Buddha I dunno.  By the info given in that thread, it seemed that is about the only symptom given that they were trying to fix.     I tried searching for that thread, but coming up empty - adidasguy had so many... I'm not sure what the title was.  I'll try to search again from google with more words.

- Bboy

Okay, that pulled it up...

I read through it again, and my recall is a little muddled lol - BUT I always read that last post in a thread after reading the OP... and if you do that, you get my recall above 

http://gstwins.com/gsboard/index.php?topic=66454.msg801159#msg801159

- Bboy

Quote from: BockinBboy on August 07, 2014, 06:17:14 AM
Okay, that pulled it up...

I read through it again, and my recall is a little muddled lol - BUT I always read that last post in a thread after reading the OP... and if you do that, you get my recall above 

http://gstwins.com/gsboard/index.php?topic=66454.msg801159#msg801159

- Bboy

It smoothed out @4k they said. Well @ rpm there is so much stuff running through it can ignore the small losses in the intake tract. But I'd be skeptical if there was no consequence.
But cool find, definitely one to keep in mind.
Cool.
Buddha.

Just threw other carbs on there and it didn't fix it.. About to open it back up and count those links I guess.