R12


Production Model Years
   1935 - 1941

Frame and Engine Numbers

   Frame numbers
    501 - 24149
    25001 - 37161
    ———
   Engine numbers
    501 - 24728
    25001 - 37161

Model Specifications
Drivetrain
Displacement745cc
Cylinders2
Bore x Stroke (mm)78 x 78
HP @ RPM18 @ 3400 (single Sum carburetor)
20 @ 3400 (twin Amal carburetors)
Compression Ratio5.0:1 (early), 5.5:1 (middle), 5.7:1 (late)
ValvesSidevalve, 2 per cylinder
ClutchDry, dual plate, cable operated
Transmission4 speed, hand shifted
Final DriveDriveshaft
Running Gear
FramePressed steel, rivetted
Front SuspensionHydraulically damped telescopic fork
Rear SuspensionRigid
Front Brakes200mm drum, single leading shoe
Rear Brakes200mm drum, single leading shoe, heel operated
Electrical
IgnitionBosch magneto (Battery/coil default on civilian models, magneto optional; magneto on all military models)
Spark PlugsBosch W175
GeneratorBosch B245 RS108 generator, 6V 45/70W, standard on civilian models, D2B R 6V 30/50W magneto/generator optional on civilian and standard on military models
Capacities & Measurements
Weight185kg
Fuel14l
Wheelbase1380mm
Top Speed110kph
Number Produced36390
First production hydraulically damped telescopic forks. Second range of frame and engine numbers matched when they left the factory. First BMW with front and rear wheels exchangeable.

The information provided here was obtained from a variety of public sources and may not reflect official BMW archival data.
Please contact the BMW Archives for official data regarding models.