Idles too high

When I got my G1200 a year ago, I found that the idle was too high, around 17-1800. It still is.

First thing I did was to put back the original muffler and install the corresponding Beetle map. No change.

I then checked the oil level, in case extra oil in the air box could affect the rev. Level was too high, so I removed half a liter, but no change.

This winter I took out the throttle bodies and cleaned them properly, - which was needed. Put them back, adjusted the valves, balanced the TBs and reset the TPS. Still no change.

Last thing I've done is to reconnect the stepper motor, which has been disconnected by one of the two previous owners.
Now it revs even higher at start up, but soon goes down to around 1700 rpm, which still is much too high.
I've only removed the blocking in the stepper tube and the corresponding filter box spigot, and reset TPS. Anything else I should do to put the stepper back in service?
PS. I did not clean the stepper motor when I cleaned the TBs, maybe I should spray some cleaner into the tube..?

So what else is there to check or do to get the idle down?

If the idle is high with the stepper disconnected, then it's likely sticking somewhere in it's travel range.

I presume you've checked for air leaks (including airbox)?

beetle wrote:

If the idle is high with the stepper disconnected, then it's likely sticking somewhere in it's travel range.

I presume you've checked for air leaks (including airbox)?

Actually I didn't give it much attention...
I checked that hoses were plugged and that the air filter was properly in place, but not for cracks or anything else.
I had to remove the RH intake hose to get the box back in place, but at least tried to put it back properly.

I guess there is no other way of testing the system for leaks than visual inspection..?

Have you balanced the throttle bodies correctly? Has the throttle stop screw ever been moved? Are both of the airbox drain hoses connected properly and plugged?

Pete Roper wrote:

Have you balanced the throttle bodies correctly? Has the throttle stop screw ever been moved? Are both of the airbox drain hoses connected properly and plugged?

I've followed your instructions when balancing the TBs, so I think they are correctly balanced. The drain hoses are cleaned and plugged.
Regarding the throttle stop screw, I will check the yellow sealing, - at least I have never touched it.

I'll go through it all again to be sure...

Connect Guzzidiag to your GRiSO and look at all three stepper values at idle speed. Check the CO Value at idle. Post the values here.

One test to evaluate if the stepper motor works: blow into the hose coming from the air filter. Switch on the ignition - at some point the stepper closes completely and afterwards opens again. If that occurs, the stepper works and opens/closes.

One some bikes the engine draws false air through the throttle shaft. The result is the engine sucks in more air at idle speed than normal and the stepper motor cannot close enough to keep the idle speed down.

Pete, I've looked through your excellent video on the TBs a few times.
About 11.20 min into the video, you explain about the drillings in the body (choke).
Are there three or two holes (I didn't think of it when I had my TB out)?
As far as I understand the one on the filter side of the throttle plate is the inlet of the tunnel and the one on the back side is the outlet. And the position of the "needle" attached to the idle screw decides how much air is going through the tunnel bypassing the t.plate. Is that correct?

If so, is the third drilling the one from the stepper? (if there is a third hole...)

Just trying to understand how this works...