Back to Bike FinderYears: 1942 · 1941 · 1940 · 1939 · 1938 · 1937 · 1936 · 1935
BMW R12 Single Carb
1937Allround

BMW R12 Single Carb

Key specifications

Engine
745 cc
Power
18 HP
Fuel type
petrol
Fuel capacity
3.7 L
Front brakes
Expanding brake (drum brake)
Rear brakes
Expanding brake (drum brake)

Overview

Introducing the 1937 BMW R12 Single Carb, a true icon in the realm of classic motorcycles. Positioned as an allrounder, the R12 captures the spirit of adventurous riding while offering a blend of style and functionality. With its timeless design and robust engineering, this model stands out as one of BMW's pioneering motorcycles in the late 1930s, appealing to both casual riders and serious enthusiasts who appreciate the artistry of vintage machines. Its sleek lines and polished chrome accents reflect the elegance of pre-war engineering, making it a collectible masterpiece for those who cherish the golden age of motorcycling. At the heart of the R12 lies a powerful 745cc two-cylinder boxer engine, delivering a respectable 18 HP at 3,400 RPM. This four-stroke powerhouse embodies the essence of BMW's commitment to performance and reliability. The R12 boasts a top speed of 110 km/h (68.4 mph), allowing riders to cruise with confidence on open roads. The bike’s well-balanced design, combined with a compression ratio of 5.2:1 and a 25mm CK carburettor, ensures a smooth power delivery and an efficient fuel consumption rate of only 3.40 liters per 100 km. This means riders can enjoy longer journeys with fewer stops for fuel, making the R12 an excellent companion for those who crave adventure. The 1937 R12 is equipped with a steel-pressed-loop frame that combines strength with lightweight agility, enhancing its maneuverability. Its telescopic front fork provides a comfortable ride, absorbing shocks from uneven surfaces, while the rigid rear suspension offers stability and control. Both front and rear expanding drum brakes with a diameter of 200 mm ensure effective stopping power, instilling confidence in riders when navigating through various terrains. Additionally, the kick starter provides a direct link to the classic motorcycle experience, connecting the rider to the machine in a way that modern electric starters cannot replicate. **

Pros

  • Timeless Design: The R12’s classic aesthetics make it a standout in any collection, appealing to vintage motorcycle enthusiasts.
  • Efficient Fuel Consumption: With a remarkable fuel economy of 69.18 mpg, the R12 allows for longer rides without frequent refueling.
  • Reliable Performance: The boxer engine delivers smooth power and dependable handling, creating an enjoyable riding experience.

Cons

  • Limited Power Output: With only 18 HP, the R12 may struggle to keep up with modern traffic, especially on highways.
  • Rigid Rear Suspension: While it offers stability, the rigid rear design may result in a less comfortable ride over rough terrain compared to contemporary models.
  • Kick Start Only: The absence of an electric starter can be challenging for some riders, particularly in difficult conditions or for those not accustomed to kick-starting.

Technical details

Source specification data

Make
BMW
Model
R12 Single Carb
Category
Allround
Starter
Kick
Power
18.00 HP (13.1 kW)) @ 3400 RPM
Ignition
Magneto
Top Speed
110.0 km/h (68.4 mph)
Fuel System
Carburettor. CK 25mm
Bore X Stroke
78.0 x 78.0 mm (3.1 x 3.1 inches)
Compression
5.2:1
Displacement
745.00 ccm (45.46 cubic inches)
Engine Details
Two cylinder boxer, four-stroke
Fuel Consumption
3.40 litres/100 km (29.4 km/l or 69.18 mpg)
Greenhouse Gases
O2
g/km. (
O2
-
Carbon
dioxide emission)
Lubrication System
Forced feed
Fuel Capacity
14.00 litres (3.70 gallons)
Overall Width
900 mm (35.4 inches)
Overall Height
940 mm (37.0 inches)
Overall Length
2,100 mm (82.7 inches)
Seat
Single seat
Rear Tyre
3.5-19
Frame Type
Steel-pressed-loop
Front Tyre
3.5-19
Rear Brakes
Expanding brake (drum brake)
Front Brakes
Expanding brake (drum brake)
Rear Suspension
Rigid-
Front Suspension
Telescopic fork
Rear Brakes Diameter
200 mm (7.9 inches)
Front Brakes Diameter
200 mm (7.9 inches)