high idle when warm - how do i fix it?

[zoltan]

this is for my girlfriend's gs500.after the engine get's warmed up it'll idle high, usually around 2200 rpm, and if she's been riding it for a while, it'll idle even higher, around 2500 rpm. another problem she's having, and i'm not sure if it's related, is if the bike is just sitting in neutral and running, if she revs it and chops the throttle, the engine winds down very slowly. any ideas what this might be and how i can fix it?

-the only mods are 125 mains and 40 pilots which we installed a couple months ago.

[octane]

I'm assuming you've already tried turning the idle adjustment thumbscrew out? Check that the throttle cable is giving you full release and not binding on something. Also that the throttle slide on the carbs is not sticking.

[The Buddha]

Well Where is the mix screws set to... Open 1/2 turn...
Cool.
Srinath.

[zoltan]

Well Where is the mix screws set to... Open 1/2 turn...
Cool.
Srinath.

you mean the ones under the brass plugs? they're turned out 3 turns from closed.

[Rema1000]

I have stock carbs on a '92 and it does this on hot days too:  
If I ride hard or stop-and-go on the freeway, then when I get off the freeway, the idle is way high at the stop lights.  The high idle actually makes it easy to start without revving to 3k .

I've heard that this is caused by lean mixture.  It only happened to me a few times during the hot days of August, and never since, so I haven't worried about it.  

Tonight's overnight forcast here is:

Rain mixing with a little wet snow north and west of the metro area. Probably wet roads in the metro, but up to 1" of slush on lawns. Low: 33

...so I'm not too worried about this becoming a problem again anytime soon.

[zoltan]

how could it be a lean situation when we installed richer jets?

[The Buddha]

3 turns is a starting point... though the typical GS seems to want to go in 1/2 a turn if you have 40 pilots in it ... out 1/2 a turn is no big deal either. I wont worry about it at all till you hit 5 turns out... close to 6 is where it quits doing anything, and it might fall out soon after  :x . Anyway also check where your floats are. they should be right at the top of the float bowl and no more. If they are set a bit low... the air screw may need to be opened to compensate, and may never be able to.
Work on jetting in winter. If you get it right in winter... well painful as it is... and test rides being much worse etc... You can be guaranteed the bike will behave in summer. Just dont go overly rich. Get it running, starting and idling perfect on a cold humid day and you are set. The criteria is the same, easy starts, quick warm up's, and good acceleration and cruise at most lattitudes... of course If you live in Switzerland and will climb the 10,000 foot matterhorn on your daily commute.... well you may have to re jet everyday up and down.
Cool.
Srinat.

[gsJack]

this is for my girlfriend's gs500.after the engine get's warmed up it'll idle high, usually around 2200 rpm, and if she's been riding it for a while, it'll idle even higher, around 2500 rpm. another problem she's having, and i'm not sure if it's related, is if the bike is just sitting in neutral and running, if she revs it and chops the throttle, the engine winds down very slowly. any ideas what this might be and how i can fix it?

-the only mods are 125 mains and 40 pilots which we installed a couple months ago.

Both of my GS's did that.  Just turn back the idle speed slowly till the revs drop back to under 1500 when it is hot.  Works for me, I've never altered the carbs.  The idle speed on a stock GS tends to pick up a bit when hot.  Just need a little choke for a mile or so when cold.  The 02 is much improved in cold running over the 97.

[ac_nvmax]

Forget all that, you see the choke cable? There is an adjustment screw on it next to lever which leans/riches the mixture. It'll be that.

Seems no-one, not even the Haynes manual knows about that adjuster.

[alerbaugh]

check the throttle spring.  It could be a little gummed up.  Thats what happened to my Super Sherpa.