BMW R51 2
1951Allround

BMW R51 2

Key specifications

Engine
494 cc
Power
24 HP
Fuel type
petrol
Fuel capacity
3.7 L
Transmission
4-speed
Front brakes
Expanding brake (drum brake). Half hub
Rear brakes
Expanding brake (drum brake). Half hub

Overview

Introducing the 1951 BMW R51/2, a classic motorcycle that effortlessly captures the essence of mid-20th century engineering and design. Positioned as an all-rounder, the R51/2 was BMW's response to the rising demand for versatile and reliable touring motorcycles post-World War II. With its distinctive boxer engine and robust construction, this model quickly became a favorite among riders seeking adventure and comfort. The blend of performance and practicality made the R51/2 an iconic symbol of the era, appealing not only to enthusiasts but also to those looking for a dependable ride that could handle a variety of terrains. At the heart of the R51/2 lies a 494cc air-cooled, two-cylinder boxer engine that delivers a respectable 24.07 horsepower at 5600 RPM. This power allows the motorcycle to reach a top speed of 135 km/h (83.9 mph), making it suitable for both city commuting and longer journeys on the open road. The four-speed gearbox, combined with a smooth shaft drive, ensures seamless acceleration and confident handling. Riders will appreciate the bike's efficient fuel consumption of 4.10 liters per 100 km (57.37 mpg), allowing for extended rides without frequent stops at the pump. The low compression ratio of 6.4:1 and the carbureted fueling system contribute to a responsive ride, embodying the spirit of adventure that BMW sought to instill in its motorcycles. The R51/2 is not just about performance; it also boasts a range of features that enhance the riding experience. The steel single cradle frame offers a sturdy foundation, while the cartridge front suspension and twin shock rear suspension ensure a comfortable ride over various surfaces. The drum brakes, both front, and rear, provide reliable stopping power, with a diameter of 200 mm (7.9 inches) to instill confidence in braking performance. With a generous fuel capacity of 14 liters (3.70 gallons), riders can embark on long journeys without the worry of running low on fuel. The classic kickstarter adds a touch of vintage charm, requiring riders to engage fully with the motorcycle, enhancing the overall riding experience. **

Pros

  • Classic Boxer Engine: The iconic design and layout provide unique performance characteristics and a distinctive riding feel.
  • Excellent Fuel Efficiency: With impressive mileage, the R51/2 allows for longer rides without frequent refueling.
  • Reliable Build Quality: The robust construction and quality components ensure durability and longevity, making it a worthy investment for collectors and enthusiasts alike.

Cons

  • Limited Power: While adequate for its time, modern riders may find the 24 horsepower lacking compared to contemporary motorcycles.
  • Drum Brakes: Although reliable, drum brakes may not offer the same stopping power and responsiveness found in modern disc brake systems.
  • Weight: At 185 kg (407.9 lbs), the R51/2 can feel heavy, particularly for inexperienced riders or when maneuvering at low speeds.

Technical details

Source specification data

Make
BMW
Model
R51 2
Category
Allround
Starter
Kick
Carrying Capacity
210kg
Power
24.07 HP (17.6 kW)) @ 5600 RPM
Clutch
Dry-single plate-cable operated
Gearbox
4-speed
Ignition
Battery
Top Speed
135.0 km/h (83.9 mph)
Fuel System
Carburettor. Bing 22mm
Bore X Stroke
68.0 x 68.0 mm (2.7 x 2.7 inches)
Compression
6.4:1
Displacement
494.00 ccm (30.14 cubic inches)
Cooling System
Air
Engine Details
Two cylinder boxer, four-stroke
Fuel Consumption
4.10 litres/100 km (24.4 km/l or 57.37 mpg)
Greenhouse Gases
O2
g/km. (
O2
-
Carbon
dioxide emission)
Lubrication System
Wet sump
Transmission Type Final Drive
Shaft drive (cardan)
Fuel Capacity
14.00 litres (3.70 gallons)
Overall Width
815 mm (32.1 inches)
Overall Height
720 mm (28.3 inches)
Overall Length
2,130 mm (83.9 inches)
Ground Clearance
120 mm (4.7 inches)
Weight Incl Oil Gas Etc
185.0 kg (407.9 pounds)
Rear Tyre
3.50-19.00
Frame Type
Steel single cradle
Front Tyre
3.50-19.00
Rear Brakes
Expanding brake (drum brake). Half hub
Front Brakes
Expanding brake (drum brake). Half hub
Rear Suspension
Twin shock-Swingarm
Front Suspension
Cartridge
Rear Brakes Diameter
200 mm (7.9 inches)
Front Brakes Diameter
200 mm (7.9 inches)