I'm having problems with my 2008 FLHT.
It has a 120R with stock throttle body opened up to 54mm by HPI.
The bike has 44,000 miles and the 120 has 15,000 miles on it.
The problem is, it started to idle a little fast at around 1100 RPM or so. And when I let off the throttle at RPM's under around 2500, it stays at that RPM for a second or 2 before the motor slows down.
Example...If I am at 2000 RPM's in second gear and let off the throttle, the bike keeps going at 2000 RPM for 1 or 2 seconds before the motor actually starts to slow down.
I've tried a few things but haven't fixed it yet.
I put on new intake manifold-to-head gaskets and no change.
I put a new map in with an idle RPM of 950 but it still idles fast.
I turned the ignition "on and wait, off and wait" 4 times to re-set the idle a couple times, but still idles fast.
I took the T-MAP sensor out and blasted it with Carb and Choke cleaner but no change.
I've unplugged and plugged back in the electric plug a few times on the TB and put on di-electric grease.
Also had 2 fault codes...P0131-Front oxygen sensor low/engine lean. And P2102-Throttle actuator control motor circuit low.
I cleared the fault codes and they haven't came back after a few rides.
Anybody know what's goin' on?

 

Can't really help you but when you say

"I turned the ignition "on and wait, off and wait" 4 times to re-set the idle a couple times, but still idles fast"

Do you wait long enough for the needles on the speedo and tack to "bump or jump"?
You will see alittle movement of both needles, at the same time

 

Yes, I wait 10 to 20 seconds between turning the main switch on and off.
The needles move, the fuel pump goes on and off and the check engine light goes on and off, then I wait a little longer.

 

If it were an older ride with throttle cables, I would suggest a weak return spring, or a sticky cable. not sure what the newer throttle bodies have for a return spring, maybe something is sticking at the trottle body somewhere untill the servo can pull itself back???
Just a though,

 

I have that happen on mine so when I throttle down I dont just let it go but twist it all the way off. Just got in the habit of doing that and dont think about it anymore.

 

Bad temp sensor might fast idle it but no idea on the return from 2000

 

my right side controls were a little tight on the the handlebars. when i would release the throttle, it wouldn't return all the way, it would bind a little. loosen your torx screws and 'nudge' your controls outward about a 1/8'' and see if that does anything.

 

I guess I forgot a couple things.
I've tried letting go of the twist grip and letting it snap back, but no change.
I've tried letting off the twist grip and rolling it backwards too, but it still takes a second or two before the engine wants to slow down.
????