Zylinderköpfe Übersicht 500 / 600 ccm

Overview of the different types of cylinder heads used on the R51/2 – R68 and 50 – R69S models Click here to view and dowload PDF file   Contributed by Erich and Matthias Lemmerer

Breather plates on the R51/3 – R69S engines

3 different breather plates have been used on the boxer engines:

Exhaust systems R50 – R69S

Table with part numbers Click here to view enlarged table  

Transmission upgrade/rebuild to “S” gearbox ratios

This modification and upgrade, using BMW components, results in a lower-ratio gearing for R26, R27, R50 and R60 gearboxes producing smoother, robust and responsive performance especially in 1st, 2nd and 3rd gear changes while 4th gear is unchanged. The “S” gear ratios allow the rider to accelerate smoothly through gear changes by letting the motor rev freely through an optimum power-torque range.

BING inserts (Mischkammer Einsatz)

Overview of the different inserts used in Bing carburetors

Crankshaft shims

Overview of the different crankshaft shims used in the boxer engines

Piston & cylinder tolerances

Piston and cylinder clearances for BMW R50, R60 and R69S (also valid for R50S and R69)

Wheel offset

Wheel offset for R51/2 – R68, R50 – R69S models (from “1000 Tricks für Schnelle BMW’s”)  

Motorcycle models

Overview of  BMW motorcycle models produced from 1948 to 1969 (specials not included) Click for larger image: Models & Production Numbers  

Valves types and related components

Overview of the different valve types and related components, used in the BMW 2-cylinder motorcycles 1948 – 1969

Fuel cocks

Overview of fuel cock types for 1 and 2-cylinders