Back to Bike FinderYears: 1942 · 1941 · 1940 · 1939 · 1938 · 1937 · 1936 · 1935
BMW R12 Twin carb
1942Sportbike

BMW R12 Twin carb

Key specifications

Engine
745 cc
Power
20 HP
Weight
185 kg
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

Introduction to the 1942 BMW R12 Twin Carb: A Classic Sport Bike Step back into the golden age of motorcycling with the 1942 BMW R12 Twin Carb, a remarkable blend of engineering and style that captures the spirit of the era. Designed as a sport motorcycle, the R12 quickly established itself as a formidable contender in the post-war landscape, appealing to enthusiasts who valued both performance and the thrill of the open road. With its iconic boxer engine configuration and sleek lines, the R12 is not just a bike; it’s a piece of history that continues to inspire riders and collectors alike. Engine Performance and Riding Characteristics At the heart of the R12 lies a powerful 745cc two-cylinder boxer engine, producing an impressive 19.99 horsepower at 4,000 RPM. This classic four-stroke powerhouse delivers a top speed of 120 km/h (74.6 mph), embodying the spirit of performance that BMW is renowned for. The air-cooled design, complemented by a sophisticated Amal carburettor fuel system, ensures a responsive throttle and an exhilarating ride. Riders will appreciate the smoothness of the 4-speed gearbox, paired with a dry multiplate clutch that provides precise engagement and control. The balanced weight of 185 kg (407.9 pounds) allows for agile handling, making the R12 a joy to navigate through twisty roads or along open highways. Key Features and Technology The R12 is not just about raw power; it's a testament to innovative engineering of its time. The steel double cradle frame offers exceptional stability, while the cartridge front suspension and rigid rear suspension maintain a comfortable ride even on uneven surfaces. Stopping power is provided by single expanding drum brakes in the front and rear, ensuring reliable deceleration as you carve through corners. With a fuel capacity of 14 liters (3.70 gallons), the R12 allows for extended rides without frequent stops, making it a perfect companion for long-distance journeys. The classic kickstarter adds a charming touch, evoking nostalgia while providing the rider with a direct connection to the machine. **

Pros

    Cons

    • Timeless Design: The classic aesthetic and boxer engine are iconic, making it a highly collectible piece.
    • Smooth Performance: The engine delivers a good balance of power and torque, ensuring a responsive ride.
    • Stable Handling: The steel frame and suspension setup provide excellent stability, enhancing rider confidence.
    • Limited Power Output: At just under 20 HP, the R12 may lack the modern performance expected by today’s riders.
    • Manual Kickstart: The absence of an electric starter can be a drawback for those accustomed to modern conveniences.
    • Weight Consideration: While stable, the R12's weight may hinder agility compared to lighter contemporary models.

    Technical details

    Source specification data

    Make
    BMW
    Model
    R12 Twin carb
    Category
    Sport
    Starter
    Kick
    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
    Lubrication System
    Wet sump
    Dry Weight
    185.0 kg (407.9 pounds)
    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)
    Power Weight Ratio
    0.1081 HP/kg
    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)