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BMW R12 Twin carb
1937Sportbike

BMW R12 Twin carb

Key specifications

Engine
745 cc
Power
20 HP
Fuel type
petrol
Fuel capacity
3.7 L
Transmission
4-speed
Front brakes
Expanding brake (drum brake). Single
Rear brakes
Expanding brake (drum brake)

Overview

Introducing the 1937 BMW R12 Twin Carb, a motorcycle that stands as a testament to the engineering prowess of its era. Positioned firmly in the sport category, the R12 epitomizes the blend of performance and style that BMW is renowned for. With its striking design and robust presence, this classic machine captures the imagination of motorcycle enthusiasts and collectors alike. The R12 not only showcases BMW's commitment to quality but also represents a pivotal moment in motorcycle history, marking the transition from utilitarian designs to more performance-focused engineering. At the heart of the R12 lies a powerful two-cylinder boxer engine, displacing 745cc and delivering an impressive 19.99 HP at 4000 RPM. This four-stroke engine, with its distinctive design and solid performance, allows riders to experience exhilarating speeds of up to 120 km/h (74.6 mph). The air-cooled engine operates with a compression ratio of 5.2:1, featuring a dual-carburettor setup from Amal that enhances fuel efficiency, returning approximately 52.27 mpg. The 4-speed gearbox coupled with a dry multiplate clutch ensures smooth transitions through gears, making the R12 an agile performer on both city streets and winding country roads. The R12's design is not just about aesthetics; it incorporates advanced technology for its time. The steel double cradle frame provides a sturdy foundation, while the cartridge front suspension and rigid rear suspension contribute to a stable and controlled ride. The drum brakes, both front and rear, offer reliable stopping power, ensuring safety without compromising the bike's vintage charm. With a fuel capacity of 14 litres, the R12 is designed for longer journeys, allowing riders to enjoy the open road without frequent refueling stops. **

Pros

  • Timeless Design: The R12 features a classic aesthetic that appeals to vintage motorcycle enthusiasts and collectors.
  • Solid Performance: With an efficient engine and lightweight frame, the bike delivers a spirited riding experience.
  • Good Fuel Economy: Its fuel-efficient design allows for extended rides, making it practical for long-distance travel.

Cons

  • Limited Power: At just under 20 HP, the R12 may feel underpowered compared to modern motorcycles.
  • Basic Safety Features: The drum brakes and rigid rear suspension may not provide the same level of performance and safety as contemporary models.
  • Kick Start Only: The absence of an electric start can be a challenge for some riders, especially in cold weather or after longer periods of inactivity.

Technical details

Source specification data

Make
BMW
Model
R12 Twin carb
Category
Sport
Starter
Kick
Carrying Capacity
300
Power
19.99 HP (14.6 kW)) @ 4000 RPM
Clutch
Dry multiplate-cable operated
Gearbox
4-speed
Top Speed
120.0 km/h (74.6 mph)
Fuel System
Carburettor. Amal
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)
Cooling System
Air
Engine Details
Two cylinder boxer, four-stroke
Fuel Consumption
4.50 litres/100 km (22.2 km/l or 52.27 mpg)
Greenhouse Gases
O2
g/km. (
O2
-
Carbon
dioxide emission)
Lubrication System
Wet sump
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)
Weight Incl Oil Gas Etc
185.0 kg (407.9 pounds)
Seat
Spring-mounted seat
Rear Tyre
3.5-19
Frame Type
Steel-doble cradle
Front Tyre
3.50-19
Rear Brakes
Expanding brake (drum brake)
Front Brakes
Expanding brake (drum brake). Single
Rear Suspension
Rigid-
Front Suspension
Cartrige
Front Brakes Diameter
200 mm (7.9 inches)