I own a 1985 K100RS. There is no obvious (to me) way to detach the throttle cable from the twist grip mechanism. I thought by removing the front brake master cylinder I would discover a place where the separation could be made, but no joy The geared wheel affair with the bit of chain cannot be lifted out of the throttle housing either.
There doesn't seem to be any description of this replacement procedure in the Haynes manual I have, and I have exhausted my ideas.
I'm stumped. Who was it that claimed it's easy to work on these bikes, anyway? After an entire afternoon in oppressive heat trying to sort this out, I'm about ready to throw in the towel and stick with my Airhead -- something a simple shade tree mechanic can make sense of.

As far as I can remember, you have to pull the entire assembly apart. The nipple at the end of the cable mounts into the chain a the inside end. I think..Been awhile.

There is a small plate on the top just to the left of the grip secured with a Phillips screw(big), the plate needs to be lifted off., it is a bit tricky. I removed the screw used a small screwdriver to wiggle it out.

Indeed, take the top plate next to the master cylinder of. It is hooked a bit under the part that holds the switches (1 screw). If you have the plate off you look on top of the little gearwheel with the chain attached. Lift the gearwheel out. Now open up the fuel rack manually (stick a screw driver under it or similar and the end of the cable on top will push the chain away (you can help it by opening the throttle. the top end of the cable is a square bit that falls into a part at the end of the chain, you can disconnect it there.
After replacing the cable, once you've guided the top end through the 'master cylinder channel' connect the gearwheel chain and slowly release the fuel rack; this will take out the slack. Once fitting back the gearwheel make sure the line on the wheel and in the grip face up. Easy job, seriously.

you may need an update kit , the motor end of the cable needs a different bracket .

I've managed to free the cable. I misspoke earlier when I said I'd removed the brake m/c. Actually I had only wrestled the fluid reservoir from the assembly. Today I removed the m/c itself which allowed me at last get at that link which hold the cable nipple. What a lot of work to change a cable!
Can you tell us more about the undated bracket on the engine end of the throttle cable?

Many thanks, Inge K.

there is a different adjuster assembly for the later cables also ....fits at the bars end and into the the chain retainer area ...consists of a nut a threaded adjuster and a flange

just a heads up

oops just saw inges link ....its got it all in there