1981 GS400L high idle

[sk88er44]

Hey guys,

I have a 1981 GS400L that runs amazing and fires up instantly. However after going for a ride and getting the motor hot, the idle seems to sit at 2000rpm. Does this seem normal? Stock intake, exhaust & carb.

[Nessism]

Check Newbie Mistakes thread linked in my signature.

[Gorminrider]

...it's normal but not right. Both my 400's did this. I was able to fix it using the idle mixture, seeing as the carbs were clean...per Nessisms list...That is, close the throttle plates as much as possible with the thumbscrew under the carbs and try to get the idle mixture to idle the bike higher. Then close the throttle some more...and adjust the idle mix some more....if adjusting the screws make no diff, then it's possible the passages need cleaning etc. It really means no gas is being sucked out the idle passages so, as per Nessism, it may point to dirt,gum or air bypassing the carbs entirely, through leaky rubber manifolds.
The idea being that the idle mixture idles the bike, the throttle accelerates and the choke merely enriches it temporarily on warmup..the choke is really an adjustable idle mixture and should not really be called a "choke" at all.

[Mekanix]

Normal. That's how you know its warmed up and thats when you should be setting the mixture.

If you try to set it while its cold or before you get a good run on it, its a waste of time. Been there many times and finally figured it out.

I set mine for highest idle when its hot and reving 2000. Change the mixture setting and reduce the idle over and over again until it reaches a point where adjusting only makes the idle drop. That's when you've found the right spot. End result is a smoother feel to the bike although when its cold the idle tends to be a little low until its warmed up.

[sk88er44]

Thanks for the replies guys