R 45

1978 BMW R 45 Technical Analysis & Specification Breakdown

Built around BMW's touring motorcycle platform, the 1978 BMW R 45 relies on a 473 cc (28.9 cu in) air-cooled two cylinder boxer, four-stroke powerplant. In factory specification, peak output is rated at 35 HP (25.5 kW) at 7,250 rpm, transferring power to the rear wheel through a 5-speed gearbox and shaft drive (cardan) final drive. With a specific output of 74 HP per liter, the engine character is indicating a tractable, stress-free state of tune focused on everyday usability and broad torque delivery.

On the scales, the R 45 measures 206 kg (454 lbs) wet (curb), translating to a power-to-weight ratio of 0.17 HP/kg (5.89 kg per horsepower). The 22-liter (5.8 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 160 km/h (99 mph).

Within MotoLibrary's BMW archive, this model family spans 7 indexed model years from 1978 to 1984, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.