When I did the inspection of the bike, the throttle and choke cables looked pretty worn with kinks showing in the outer armor. The Bowden connector rubber boots are disintegrating. I’m replacing the cables before riding the bike as I don’t want a stuck throttle or broken cable to happen. I found removing the cables from the Bowden connector required a little technique, but once I figured this out for the choke, the throttle was done pretty quickly.
You know, being retired just seems to leave no time to work in the shop. I end up doing all sorts of things and the next thing you know, time for bed. Anyway, I finally wrote up the Bing carburetor rebuild/refinish work I did on the 1983 R100RS project.
When I rebuilt a 1973 BMW R75/5, I covered the procedure I used to rebuild the Bing type 64 carburetors, which are 32 mm, and the Karcoma petcocks. The R100RS has type 94 carburetors that are 40 mm and the Karcoma petcock outlet is 90 degrees from the inlet instead of directly underneath the inlet as for the R75/5. After 10 years, the designs are essentially the same, but there are some differences which I cover in the procedure write-up.
Here is the link to the R100RS Bing type 94 rebuild/refinish procedures.
The R100RS write-up contains links to the R75/5 procedures for the Bing type 64 carburetor and notes any differences or changes in how I did the work on the R100RS carburetors. Here is the link to the R75/5 type 64 carburetor rebuild/refinish procedures.
The combination of these two write-ups covers the type 64, 32 mm (64/32/10, right side and 64/32/9, left side) and the R100RS type 94, 40 mm (94/40/114, right and 94/40/113, left) carburetors.
I hope this material makes it straight forward for folks to rebuild these carburetors who may have been afraid to tackle a carburetor rebuild. Here are some before and after pictures of the carburetors.
Before-R100RS Type 94 Left Carburetor
Rusty Screws and Cap on Dome
Grunge and Fuel Stains
Float Bowl Removed, Missing Paint on Emblem
Engine Side of Restored / Rebuilt Carburetor
Top Side of Restored / Rebuilt Carburetor
Outlet Side of of Restored / Rebuilt Carburetor
After-R100RS Type 94 Rebuilt and Refinished Carburetor
Based on the inspection, I plan to do a major service, carburetor and petcock rebuild, and any other essential maintenance. Then I will ride the bike for a couple hundred miles so I have a baseline for how the bike runs and handles before I dive into the rebuild.