The following tech note involves a problem on my 1978 R100S. The issue does not exist on either of my '81 and '83 R65s.
I discussed fitting new floats and float needles in another thread. So as I was already in there with the carbs removed, it was a good time to replace the POs poorly routed and damaged throttle cables. Note the stretched and damaged cable where it enters the cable adjust ferrule.
Shrink tubing does a poor job of providing support either before or after fitting extra-wide street tracker-style handlebars and keeping the OEM 1027mm cables made for the 'S' low Euro bars.
I did reroute the cable runs for smoother arcs and a more direct, vertical entry into the ferrules. The concern was maintaining their position and avoiding a repeat failure. I'd previously gone back to the proper "S" handlebars.
I recalled having cable stays on a few previous motorcycles. Just simple bent wire anchors.
Made up a ghetto-style wire bending tool and used 3/32" brass wire to fab my own throttle cable stays. Anchored by the engine's top cover Allen screws, all that was necessary was to Dremel grind reliefs that would permit attaching the stays and allow for small adjustments. Everything came together after some touchup paint on the case. As the new stays are fairly short and are all but hidden by the petcocks, I believe the cables will be safe from damage.