1927 BMW R39 Technical Analysis & Specification Breakdown
Engineered by BMW for the naked motorcycle segment, the 1927 BMW R39 features a 247 cc (15.1 cu in) air-cooled single cylinder, four-stroke configuration. In factory specification, peak output is rated at 6 HP (4.4 kW) at 4,000 rpm, transferring power to the rear wheel through a 3-speed gearbox and shaft drive (cardan) final drive. With a specific output of 24.3 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 R39 measures 110 kg (243 lbs) wet (curb), translating to a power-to-weight ratio of 0.05 HP/kg (18.33 kg per horsepower).
Within MotoLibrary's BMW archive, this model family spans 2 indexed model years from 1926 to 1927, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
