Here's the problem. When the bike is warmed up the idle will spike and you can't knock it down until it comes down by itself. (takes about 15 seconds to come down and goosing the throttle has no effect). This could happen while moving which isn't pleasant or when you stop at a light.
Any ideas about where to start looking? ECM, vacuum, fuel injection etc.
The cableand butterflies in the throttle body seem to be working ok.

 

I am guessing you tried the throttlecable binding, pulling, or pinching,depending on turning the handle bars.

 

All that looks fine

 

Has he ever serviced his push - pull cables...

Had a friend that had the same type of problem (his was carb) - found out he never serviced his cables... Pulled them down dirty & dry causing on cable to burr and was binding at times... Outside of that is his Ck Engine Lite lit? (it should set a code if its the ecm or the injector?)

 

The idle spike can happen while you are drivingwith a constant throttle position so that makes me rule out push, pull cables.

 

had a cable liner bur, actual cable looked good. But you still could feel pressure/sticking on throtle if that were the culprit ,my guess?

 

personally I believe you have an electronic glitch.
Have you pulled the trouble codes up on the speedo?
So many variables could cause this.
so diagnosing is the way to go.
Get the service manual and the electronics manual for this bike.
The head temp sensor may be failing.
Giving an abnormal HOT reading to the ECM.
Ecm increases fuel momentarily and possibly the ISC to raise idle and help
cool engine and or change the timing.
You need the manual to be able to test the compnents.
Do you have the SERT installed? if so with a laptop you can read the data history. If not need to see the dealer and put the scanner on it.
Or the TPS could have a glitch ut not as likely.

 

Was talking to a wrench today. He suggested the IAC motor may be bad.

 

Have you checked for an intake leak?

 

agree with choochoo, consider looking at the engine temp. sensor..get the h-d service book..
note: DO NOT OVER TIGHTEN...one member reported having to buy two because it cracked..
basic tools..need 3/4 inch deepwell socket and small hands help.