1938 BMW R12 Single Carb Technical Analysis & Specification Breakdown
Positioned in BMW's allround motorcycle lineup, the 1938 BMW R12 Single Carb relies on a 745 cc (45.5 cu in) two cylinder boxer, four-stroke powerplant. In factory specification, peak output is rated at 18 HP (13.1 kW) at 3,400 rpm. With a specific output of 24.2 HP per liter, the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.
Rider ergonomics and chassis geometry center around a 1,380 mm (54.3 in) wheelbase engineered for quick, flickable steering geometry. The 14-liter (3.7 US gal) fuel tank paired with a rated consumption of 3.4 L/100 km provides an estimated theoretical range of roughly 412 km (256 miles) between fill-ups, while factory top speed is listed at 110 km/h (68 mph).
Within MotoLibrary's BMW archive, this model family spans 8 indexed model years from 1935 to 1942, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
24.2 HP/L
Theoretical Range
~412 km (256 mi)
Engine
Displacement745.0 ccm (45.46 cubic inches)
Engine TypeTwo cylinder boxer, four-stroke
Engine DetailsTwo cylinder boxer, four-stroke
Power18.0 HP (13.1 kW)) @ 3400 RPM
Compression5.2:1
Bore x Stroke78.0 x 78.0 mm (3.1 x 3.1 inches)
Fuel SystemCarburettor. CK 25mm
Fuel ControlStanding valves
IgnitionMagneto
LubricationForced feed
Performance
Top Speed110.0 km/h (68.4 mph)
Fuel Consumption3.40 litres/100 km (29.4 km/l or 69.18 mpg)
Greenhouse Gases78.9 CO2 g/km. (CO2 - Carbon dioxide emission)
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.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
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.
