I have recently purchased a 2000 GS500.  When I first got it home, it idled low (600ish RPMs) and had very muted throttle response.  I figured it was probably just bad gas from last year and perhaps carbs that were a bit gummed up.  I drained the old gas put in a fresh gallon with a couple of ounces of Seafoam.  I fired it up, let it warm up, and after turning the choke off, it idled okay (1100-1200ish RPMs).  The throttle worked just how anyone would want it to.    I did notice when draining/filling up, that there was a little rust in the tank--not anything too severe.  Anyway, I didn't have the bike registered at that point, so I didn't take it out.  I topped off the fuel tank and pushed it back into the garage.  A few days later, I got all of my paperwork straight, and figured I would take it for a spin despite it needing some fresh rubber.  The bike started quickly, warmed up, and the idle was normal when I turned the choke off.  I went for a short ride (only a mile or so before turning around), and by the time I was on my way back, anytime I would pull to a stop and pull in the clutch the bike would settle at no less than 3500 RPMs (pretty much exactly 3500)--needless to say a little disconcerting for restarts.  After first warming the bike up, it had idled just about perfect at 1200 or so--even at all the stops over the first 1/2 mile or so.  Perhaps rust has worked its way into the carbs. I did see another post that suggested somebody with the exact same 3500 RPM idle had clogged pilot jets?

Input?
--theUBS

Theres a little screw between the carbs the idle screw , seems what u did is have the cold idle , when the bike gets hot , then Carefully ill add , adjust the screw down

if that doesnt work , then look into ur carbs

dang i feel like i have the same problem except mine goes up to 4000RPM.

i don't know what my problem is but i think it might be the carbs not sure

was going to clean them out and do a valve adjustment at the same time but i think thats changed now since east coast valve adjustment set its gone.

i'll be checking this thread for tips thanks for posting ur problem lol i hope somebody knows 

tiem for a clean up ( of teh carbs), or take it out, and give it hell first, and see if it does it again

i've got the same problem. i think it only started when i tried to adjust the idle screw and the bike just wasn't warm enough yet. gonna ride around a bit and see if i can adjust it better.

Try this.

First, I assume you have cleaned carbs or at least run some fuel system cleaner and your bike runs relatively good except you have this hanging idle thing.

Before you get started set your idle mixture screws to 2 to 2.5 turns out. Some factory bikes will have plugs over the mixture screws that needs to be removed.  Requires carbs to be removed and modified by drilling out the plugs.  You will need access to the mixture screws.

Now, take the bike for a ride so the full operating temp is reached.

Stop the bike and leave it idling, if it is idling high load it so that it comes down.

In any case adjust the idle speed screw with your hand down to 900-1000 rpm. Blip the throttle a couple times and make sure it is stable.

Now, turn the mixture screws, 1/2 a turn at a time one side then the next to keep them even.  Do this until you reach a new idle speed of around 1200-1300.

Report your results after you have had a couple of cold starts and hot runs to see if this is a stable setting for your bike. 

birdman

Well, today I figured I would just try the idle adjustment.  I started the bike and left it running until the high idle resurfaced.  This took just about a solid 10 minutes of running.  In all honesty, I'm not exactly sure how long I should have to leave the bike running to reach full operating temperature.  10 minutes seems almost excessive--especially in 65 degree weather.  How long should the bike have to be choked, and at what RPM should you attempt to keep the engine running at during the warm up period?  ANYWAY, after the high idle returned, I turned it down to about 1200-1300 and the bike seemed to run fine if only for the short run it was taken on.  I guess only a longer ride will tell me if this was the true solution to my problem.  However, I might have to wait on new tires before I can really give it the good run it needs.  The tires that are on it are pretty much shot.  The rear is pretty thin, and the front is dry-rotted and seems to want to pull the bike to the left. 

Just ordered a set of Avon Roadriders.  Hopefully they'll be mounted up by weeks end!  Thanks for all the input.

Quote from: dleemiller on May 04, 2008, 02:38:29 PM
i've got the same problem. i think it only started when i tried to adjust the idle screw and the bike just wasn't warm enough yet. gonna ride around a bit and see if i can adjust it better.

I haven't verified it yet, but I'm almost guessing the previous owner turned it up the day I picked up the bike.  It was a little bit cooler that day and he had it running when I got there.  The bike probably wasn't running properly either--due to the old gas that was in it.  He might have cranked it up pretty good for all I know.  If I ever get a hold of him I'll have to ask.

Quote from: theUBS on May 04, 2008, 08:23:09 PM
How long should the bike have to be choked, and at what RPM should you attempt to keep the engine running at during the warm up period? 

I never use my choke for very long. I start w/ full choke once the engine begins to reve above 2K I start to adjust the choke off till it idles at about 2K.. .I let it run like that for about a min or so while I put on my helmet and gloves, then I shut the choke off and she idles a little lower than 1.5K

My bike starts and runs about the same no matter what the outside temp. I have started it the same weather it was 30F or 90F 

Quote from: scottpA_GS on May 05, 2008, 10:03:44 AM
I never use my choke for very long. I start w/ full choke once the engine begins to reve above 2K I start to adjust the choke off till it idles at about 2K.. .I let it run like that for about a min or so while I put on my helmet and gloves, then I shut the choke off and she idles a little lower than 1.5K

My bike starts and runs about the same no matter what the outside temp. I have started it the same weather it was 30F or 90F 

Thanks a bunch.  Our climates should be similar enough for that to be about right.  Do you usually have yours garaged at a fairly consistent temperature?  I do notice that if fully choked it'll shoot up to 4k+ within just a few seconds--particularly on warmer days--and I usually back it off a bit.  Is there a target RPM range to keep the engine running at during the warm-up?  Do you run stock carbs too?  Thanks again for your input!