Another Idle Inquiry

[Nugpop]

Hello all, apologies for initiating a new thread on a much discussed topic. My head is spinning from all of the various possible culprits and solutions presented in previous ones. Specifically, I'm talking about the hanging/high idle when warm thing. The bike starts and runs great, however the idle stays up at around 3-4 k once it warms up. Idles great at 1-1.5 when cold. After considering the fact that this is a widely encountered issue, it should follow that with regards to this particular bike (excluding the usual suspects that have been ruled out), it has a common cause. Can anyone disclose what that common cause is? It's unlikely, as previous responses indicate, that identical high idle when warm symptoms are occurring on identical bikes but have varied solutions (I read everything from spark pugs to coils to valves to synch to air leak to....) Again, apologies if this cause was previously presented...sorting through it all was generating enough frustration to throw wrenches before I began!

 

[NewHavenMike]

Did you set your idle when the bike was warmed up? I know my bike will idle pretty low when I first start it. Then it will creep up to 1500-1700 and stay there very stable. So if you set your idle at 1500 when its cold, you should rev around 500 rpms higher when its warm.

The timing advance not returning to "home position" could be a problem if you have a mechanical advance. Other problems could be that youre too lean with fuel adjustment..

I also had an issue with my throttle cable where the throttle would stay slightly open or stick, and I always thought it was the idle adjustment screw.

Make all your adjustments with the bike warm, EXCEPT valve adjustments.