BMW R51 2
1950Allround

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

The 1950 BMW R51/2 stands as a quintessential example of post-war motorcycle engineering, combining classic design with innovative technology that was ahead of its time. Positioned firmly in the allround category, this bike appealed to a diverse range of riders—from daily commuters to adventure seekers. With its distinctive boxer engine and elegant lines, the R51/2 not only turned heads but also set a benchmark for reliability and performance in the motorcycle market of the era. At the heart of the R51/2 is a robust 494cc, two-cylinder boxer engine, producing a commendable 24.07 horsepower at 5600 RPM. This four-stroke powerhouse delivers a top speed of 135 km/h (83.9 mph), making it a capable companion for both city rides and countryside excursions. The engine features a 6.4:1 compression ratio and is fed by a Bing 22mm carburettor, ensuring smooth power delivery throughout the rev range. The air-cooled design, coupled with a 4-speed gearbox and a reliable shaft drive, provides riders with a wonderfully engaging experience—characterized by a low center of gravity and superb road handling that makes navigating twisty roads a delight. The R51/2 is not just about performance; it also showcases several key features that highlight BMW's commitment to quality and rider comfort. The steel single cradle frame provides a sturdy foundation, while the dual drum brakes—both front and rear—ensure reliable stopping power. The suspension system, featuring cartridge front suspension and twin shock rear suspension, contributes to a smooth ride, soaking up bumps with ease. With a fuel tank capacity of 14 liters and an impressive fuel consumption rate of 4.10 liters per 100 km, this motorcycle is as practical as it is stylish, making it ideal for long journeys. **

Pros

  • Classic Design: The R51/2’s timeless aesthetic appeals to vintage motorcycle enthusiasts and collectors alike.
  • Smooth Handling: The boxer engine and low center of gravity provide excellent stability and handling, making it easy to maneuver in various conditions.
  • Fuel Efficiency: With an impressive fuel consumption of 57.37 MPG, this bike is economical for both daily commuting and long-distance rides.

Cons

  • Limited Power: While adequate for its time, the power output may feel modest to modern riders accustomed to higher-performance machines.
  • Kick Start Only: The traditional kick starter may deter some riders who prefer the convenience of electric start options.
  • Heavier Weight: At 185 kg (407.9 lbs), the R51/2 can feel heavier compared to contemporary lightweight models, potentially making it less appealing for newer riders.

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)
Seat
Solo seat with springs
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)