R51 2

1951 BMW R51 2 Technical Analysis & Specification Breakdown

Built around BMW's allround motorcycle platform, the 1951 BMW R51 2 features a 494 cc (30.1 cu in) air-cooled two cylinder boxer, four-stroke configuration. In factory specification, peak output is rated at 24.1 HP (17.6 kW) at 5,600 rpm, transferring power to the rear wheel through a 4-speed gearbox and shaft drive (cardan) final drive. With a specific output of 48.8 HP per liter, the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.

On the scales, the R51 2 measures 185 kg (408 lbs) wet (curb), translating to a power-to-weight ratio of 0.13 HP/kg (7.68 kg per horsepower). Rider ergonomics and chassis geometry center around a 1,400 mm (55.1 in) wheelbase engineered for quick, flickable steering geometry. The 14-liter (3.7 US gal) fuel tank paired with a rated consumption of 4.1 L/100 km provides an estimated theoretical range of roughly 341 km (212 miles) between fill-ups, while factory top speed is listed at 135 km/h (84 mph).

Within MotoLibrary's BMW archive, this model family spans 2 indexed model years from 1950 to 1951, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.