Brake Master Cylinder - 14mm for Rear Brakes on R100 Models
The cylinder was originally a 15mm bore however BMW retrospectively superceeded this with the 14mm.cylinder. The rider will hardly notice the difference - the brake lever has slightly more travel and the brakes are slightly more powerful.
No longer available from BMW
NOTE: See BMCylinder960 for the master cylinder post 09/80 and BMCylinder233 for Master Cylinder Rebuild Kit.