251 OSL

1933 NSU 251 OSL Technical Analysis & Specification Breakdown

At the heart of the 1933 NSU 251 OSL sport motorcycle, NSU features a 242 cc (14.8 cu in) air-cooled single cylinder, four-stroke configuration. In factory specification, peak output is rated at 9 HP (6.6 kW) at 5,000 rpm, transferring power to the rear wheel through a 4-speed gearbox and chain final drive. With a specific output of 37.2 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 251 OSL measures 126 kg (278 lbs) dry, translating to a power-to-weight ratio of 0.07 HP/kg (14 kg per horsepower). Rider ergonomics and chassis geometry center around a 1,285 mm (50.6 in) wheelbase engineered for quick, flickable steering geometry. The 11.5-liter (3 US gal) fuel tank paired with a rated consumption of 2.3 L/100 km provides an estimated theoretical range of roughly 500 km (311 miles) between fill-ups, while factory top speed is listed at 100 km/h (62 mph).

Within MotoLibrary's NSU archive, this model family spans 8 indexed model years from 1933 to 1940, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.