Engine idle hunting

[dorris1988]

My gs500 tends to rev up when im stationary. it only does this when town driving, never when im doing long distance. it never goes past 3000. its a 1991 so its seen better days. could this just be because of its age? this is the only reason ive heard.

[newbie]

I just had the same problem, it was the o-rings in the carbs. After they were replaced and carbs cleaned it runs great and idles down to 12k

[KasbeKZ]

down to 12k? if you are above 12k there.... owch.

1.2k *

[bill14224]

I hunt my idle with a 12-gauge shotgun. 

Air leaking into the carbs where it shouldn't will make the idle rise.  Boots and O-rings like newbie said will do it.  So will a leaky vacuum tube to the carbs from the petcock.  On the road you wouldn't notice it because you're not at idle on the open road.

[The Buddha]

Lean or other wise sucking air, can do that as can the hanging cables (throttle or choke)
Cool.
Biddha.

[Agno]

I have had a similar issue for some time now.  After the bike is fully warmed up it will want to hover around 4k.  I reach under and back out my idle screw about half a turn.  That usually solves that issue.  At least until I cold start the bike again and the bike tries to idle at 500rpm and dies.

So I have just been going back and forth with the idle screw.  Works, a bit annoying, but it works.


And on a humorous note:  My little brothers eyes looked like dinner plates when the idle shot to 4k while he was learning how a clutch worked for the first time.