glad you made the switch , as far as high idle could be be lots of possibilities. Does it idle high when cold ? Could be as simple as throttle cables need slacking off if high idle when cold also . I would start with that to see if is slight slack in both cables when throttle closed. if they have slack then could be air leak in where rubber and carbs meet up make sure rubber is tight and not leaking holes or rotted . when running can spray some carb cleaner on rubbers and if it goes down probably air leak . I would start there.

Thanks for the response 11108
It idles fine when cold so the cable slack should be ok.
I'll look for leaks as you suggest.
I read something about advance unit springs wearing out.
Perhaps that is at fault?
Thanks again for the response.
Cheers,
-Marcus

First off, thank you for joining the Airheads Beemer Club.(ABC)
Slow to return to idle when warmed up is an indication of a sticking centrifugal advance mechanism. If you are able to slow the idle speed clutching out while holding the brakes, this is another indicator. The advance unit is located on the front of the cam shaft under the front motor cover. Be sure to dis-connect the battery when removing the front cover.
If it were my bike, I would first try cleaning the advance mechanism by spraying the unit with brake cleaner and then drying it with compressed air and then applying a little lubricant to the pivot points where the fly-weights are held on to the unit. New springs might be a good idea, but be careful. They are easy to lose.

if your problem is only after it warms up i think it is most likely the advance unit.

8053 & 11108, thank you very much for the responses and details. Much appreciated. I'll put your advice to work.

Scot, message heard loud and clear. I'll be sure to post technical questions in the Tech area or My Airhead needs help.

Cheers all,
-Marcus