Hi guys- my 2 cents, and thanks for your excellent input, I do appreciate it
To PAS -Our throttle shafts/bushings were worn mainly on the cable/spring side.
We also had '81 and '83 R100RT's in Aussieland, we put on 30k km, carbs similar to yours , dusty conditions, shafts wore like crazy.
To nrp -Ball not roller bearings with 2 Side Shields, but I agree they may eventually become contaminated. But I avoided replacing the shafts and bushings which would fail again eventually anyway.
To Roger - I may someday turn the TPS to the indicated voltage for idle, which I believe would end up really close to the same result.
( joke) - I just checked and the throttle stop screw does fit in my lawnmower :-)
To dirtrider -Re: Bushings are a "correct choice", I could agree, especially if they lasted :-), maybe a larger diameter surface area on the cable side, different materials.
( joke) it's a Beemer, it doesn't vibrate :-)
To the world ( and Dan Cata) - ! ( light bulb) If a person ( named Dan) made a stepped nylon/teflon/oilite/unobtainium bushing that also filled the 13mm recess, with an o-ring on the end, instead of the shaft, thereby giving more surface area
And/OR made a throttle shaft with a larger diameter on the cable side ( up to the cable pulley), bored the Throttle body ( cable side) to a larger diameter, inserted a nylon/teflon/oilite/unobtainium bushing that would wear instead of the shaft,
-( joke) could also add a harley chain oiler for bushing lubrication :-) . OK, that's not funny.
--OK, back to the shop, don't touch wife's bike, don't touch wife's bike, don't touch wife's bike,
Come to think of it, It's working fine. Put my hands in my pockets, walk away.