I don't know if it is the same design, but the throttle on my 201 was sticking for a while too. The shops couldn't fiqure it out, but I did. There is an arm that runs from all the throttle arm linkage across the engine. I replaced all the ball joints there, thinking that was the problem. However the one ball joint the shop didn't change was the problem. The metal rod that runs parallel to the windshield, towards the engine has a ball joint on it too, over the engine (this is hidden well, you have to look good to see it). I noticed that when the throttle was depressed, the ball joint was a little loose. This allowed the joint enough free play to get hung up on a bolt head. You could see this because the bolt head had been rubbed, so it was shinny. Plus I could move the throttle linkage and occasionaly make it stick on the bolt head, causing the throttle to stay open. The solution was simple. Tighten the ball joint so there was no free play. Since doing that my throttle has never stuck again. Hope this helps.
MBCA, PCA, BMWCCA & SCCA* member
86 190 2.3-16
83 944 ITS Racer