R25 2

1951 BMW R25 2 Technical Analysis & Specification Breakdown

Engineered by BMW for the allround motorcycle segment, the 1951 BMW R25 2 utilizes a 247 cc (15.1 cu in) air-cooled single cylinder, four-stroke layout. In factory specification, peak output is rated at 12 HP (8.7 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 48.6 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 R25 2 measures 140 kg (309 lbs) wet (curb), translating to a power-to-weight ratio of 0.09 HP/kg (11.67 kg per horsepower). Rider ergonomics and chassis geometry center around a 730 mm (28.7 in) seat height — giving shorter riders and urban commuters confident flat-foot reach at traffic stops, combined with a 1,335 mm (52.6 in) wheelbase engineered for quick, flickable steering geometry. The 12-liter (3.2 US gal) fuel tank paired with a rated consumption of 2.9 L/100 km provides an estimated theoretical range of roughly 414 km (257 miles) between fill-ups, while factory top speed is listed at 80 km/h (50 mph).

Within MotoLibrary's BMW archive, this model family spans 3 indexed model years from 1951 to 1953, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.