The Vintage Motorcycles
Specialists in antique, classic, veteran and vintage motorcycles.
Specialists in antique, classic, veteran and vintage motorcycles.
The 1931 BMW R2 was introduced as BMW's return to the small-capacity motorcycle market and became the company's first series-production single-cylinder motorcycle since the earlier R39. With a 198cc overhead-valve engine, pressed-steel duplex frame, shaft final drive, and simple three-speed transmission, the R2 brought several of BMW's characteristic engineering principles into a much more affordable motorcycle.
The R2 was developed for the growing German market for motorcycles below 200cc. From 1928, motorcycles up to 200cc benefited from important tax and licensing advantages in Germany, creating an opportunity for manufacturers to offer inexpensive transportation to a much broader group of riders.
For BMW, the R2 was an important strategic model. The company's larger Boxer motorcycles were relatively expensive, while the economic conditions of the early 1930s made affordable transportation increasingly important. The R2 allowed BMW to compete in this lower-cost segment without abandoning the quality and engineering identity associated with its larger motorcycles.
The 1931 R2 Series 1 uses BMW's M67 198cc air-cooled vertical single-cylinder engine. It produces 6 horsepower at 3,500 rpm and uses overhead valves, a 6.7:1 compression ratio, and a 19mm Sum carburetor.
Although small compared with BMW's large-capacity motorcycles, the R2 retained shaft final drive and a pressed-steel duplex frame. These features gave the motorcycle a distinctly BMW character and demonstrated that the company was not simply building a stripped-down economy machine.
The R2 Series 1 was produced only during 1931, with 4,161 examples built. The model subsequently evolved through several series, eventually increasing output to 8 horsepower and remaining in production until the middle of the decade.
The 1931 BMW R2 is therefore important not only as a small pre-war motorcycle, but also as the model that helped BMW establish a successful line of lightweight single-cylinder motorcycles during one of the most difficult economic periods in European history.
BMW introduced the R2 in 1931 as the company's answer to the growing demand for affordable motorcycles. The economic crisis following the 1929 Wall Street crash had reduced demand for expensive motorcycles, making a smaller and less costly BMW particularly important.
The R2 was positioned below BMW's larger motorcycles and was designed to take advantage of the German regulations applying to motorcycles below 200cc. Its 198cc displacement kept it within the important sub-200cc category.
The original R2 Series 1 carried a price of 975 Reichsmarks in 1931. Although this was still expensive compared with some competing lightweight motorcycles, customers were buying a genuine BMW with engineering and construction principles shared with the company's larger machines.
Production of the Series 1 began and ended in 1931, with 4,161 motorcycles produced. The model then evolved into the Series 2A, Series 2/33, Series 3, Series 4, and Series 5.
The later versions introduced a number of incremental changes. The exposed valve springs of the Series 1 were enclosed on the Series 2A, while a steering friction damper was added during the Series 2/33 production period.
The carburetor was also progressively developed. The early R2 used a Sum carburetor, while later versions adopted an Amal carburetor that eventually increased engine output from 6 horsepower to 8 horsepower.
BMW Group Classic records production of the R2 from 1931 through 1937, with more than 15,000 motorcycles produced across the model's complete production history. Some historical production references give 1931-1936 as the production period, so the broader BMW Group Classic date is retained here for consistency with BMW's own archive information.
A surviving 1931 R2 is particularly significant because it represents the original Series 1 specification and the first production year of BMW's successful lightweight single-cylinder program.
The 1931 BMW R2 is powered by the M67 engine, a 198cc air-cooled four-stroke vertical single-cylinder unit with overhead valves. The engine has a 63 x 64 mm bore and stroke and a compression ratio of 6.7:1.
The engine produces 6 horsepower at 3,500 rpm. This modest output was appropriate for the R2's intended purpose as economical everyday transportation rather than high-speed touring or sporting use.
The original Series 1 uses a 19mm Sum carburetor. The carburetor and relatively low compression ratio were designed around dependable operation and practical running costs rather than maximum performance.
BMW's M67 engine uses forced-feed lubrication supplied by a gear-driven oil pump. This provided controlled lubrication for the engine while retaining a straightforward mechanical design suitable for a lightweight motorcycle.
The R2 has a claimed top speed of approximately 95 km/h. This was sufficient for the road conditions and intended role of the motorcycle during the early 1930s.
The vertical single-cylinder configuration is considerably different from BMW's famous Boxer engines, but the R2 still reflects the company's emphasis on robust construction, effective cooling, and practical mechanical design.
The engine's relatively low output also helped keep operating stresses manageable. For an economy-focused motorcycle intended to provide dependable transportation during difficult economic conditions, durability and low running costs were more important than outright speed.
The R2 Series 1 uses a three-speed manual transmission with a single-plate dry clutch. The gearbox ratios are approximately 2.89, 1.70, and 1.00 to 1.
The three-speed arrangement was sufficient for the R2's 6-horsepower engine and lightweight road-going role. It provided a simple and durable drivetrain without the additional mechanical complexity of a four-speed transmission.
One of the most distinctive features of the R2 is its shaft final drive. BMW used a cardan shaft to transfer power from the gearbox to the rear wheel, maintaining a mechanical feature strongly associated with the company's larger motorcycles.
The final-drive ratio of the Series 1 is approximately 6.75:1. The relatively low gearing was appropriate for the small engine and helped the R2 make effective use of its limited power.
The shaft-drive arrangement also reduced the need for routine external chain maintenance. This was particularly appropriate for a motorcycle marketed as practical and economical transportation.
The R2 therefore combined a simple three-speed gearbox with a relatively sophisticated shaft final drive, giving the small motorcycle a drivetrain that was distinctly BMW in character.
The R2 Series 1 uses a pressed-steel duplex frame designated F67. The frame was an important part of the motorcycle's design and provided a strong structural platform while allowing BMW to manufacture the machine economically.
The use of pressed steel distinguished the R2 from many motorcycles that relied primarily on tubular steel frames. BMW also used pressed-steel construction on larger motorcycles of the period, giving the R2 a direct connection to the company's broader chassis engineering.
At the front, the R2 uses a nine-lamina cantilever spring suspension system. The arrangement is mechanically simple and reflects the suspension technology available before BMW's later adoption of hydraulically damped telescopic forks on the R12 and R17.
The rear suspension is rigid, with the rear wheel mounted directly to the frame. Rider comfort was therefore provided primarily through the sprung saddle and the front suspension.
The chassis uses 25 x 3 wheels and tires at both ends. Drum brakes with approximately 180mm diameter drums provide braking at the front and rear.
The wheelbase measures approximately 1,320mm, contributing to the R2's compact proportions and manageable handling. The overall dimensions are approximately 1,950mm in length, 850mm in width, and 950mm in height.
The R2's chassis demonstrates the balance between cost-conscious construction and BMW's established engineering standards. It is simple, but it is not a bare-bones design.
The 1931 BMW R2 has the distinctive appearance of an early-1930s European motorcycle, with a large fuel tank, substantial mudguards, wire wheels, exposed engine components, and an upright riding position.
The pressed-steel frame gives the motorcycle a smooth and substantial appearance while providing the structural foundation for the engine and drivetrain.
The vertical single-cylinder engine occupies a visually prominent position in the frame. Unlike BMW's larger Boxer models, the R2 has a narrow engine profile that contributes to its compact appearance.
The shaft-drive rear wheel is another important visual and mechanical identifier. Even though the R2 was designed as a lightweight motorcycle, BMW retained the cardan-drive arrangement associated with its premium motorcycles.
The original Series 1 can also be distinguished by its exposed valve springs at the top of the cylinder head. Later R2 versions enclosed these springs, making the early 1931 configuration particularly recognizable.
The overall design is functional rather than luxurious, but the motorcycle retains the engineering and visual character expected from BMW during the early 1930s.
The R2 was introduced at a crucial moment in BMW's development. The company had established itself with larger motorcycles, particularly its Boxer-powered models, but those motorcycles were expensive at a time when economic conditions were severely restricting consumer spending.
The sub-200cc motorcycle category offered BMW access to a broader customer base. The R2's 198cc displacement was deliberately chosen to remain below the important 200cc threshold under German regulations of the period.
This strategy allowed BMW to offer a motorcycle with lower purchase and running costs while retaining engineering characteristics that distinguished it from cheaper competitors.
The R2 was joined by larger single-cylinder models such as the 305cc R3 and 398cc R4. Together, these motorcycles gave BMW a much broader range of products than the company's earlier focus on larger-capacity machines.
The R2 was particularly important because its relatively low cost made BMW ownership accessible to riders who could not afford the company's larger motorcycles.
The model's commercial success demonstrated that BMW could compete effectively in the lightweight market while maintaining its reputation for quality and engineering.
The 1931 Series 1 represents the original R2 specification. Its most recognizable technical feature is the exposed valve-spring arrangement on top of the finned cylinder head.
For 1932, BMW introduced the Series 2A, which enclosed the valve springs and introduced other detail improvements. The basic 198cc engine and pressed-steel chassis concept remained intact.
The Series 2/33 followed with further development. A British Amal carburetor was offered on some examples, and a friction steering damper was introduced from June 1933 to improve steering control.
For 1934, the Series 3 adopted the Amal carburetor as the standard carburetion arrangement. The change increased engine output from the original 6 horsepower to approximately 8 horsepower at 4,500 rpm.
The Series 4 followed in 1935 with changes including a smaller fuel tank and modified headlight. These details illustrate how BMW continued refining the motorcycle without fundamentally changing its basic engineering.
The Series 5, produced toward the end of the model's life, received a revised shaft-drive ratio and a wider rear mudguard incorporating the license-plate holder.
These progressive changes make the 1931 Series 1 especially important to collectors because it preserves the earliest configuration of a motorcycle that subsequently evolved considerably during its production life.
The R2's mechanical character is defined by simplicity and practicality. Its 198cc single-cylinder engine delivers modest power, but the motorcycle was designed to provide economical and dependable transportation rather than sporting performance.
The vertical single-cylinder layout is straightforward and relatively easy to service. The overhead-valve design provides a more efficient breathing arrangement than a side-valve engine while remaining mechanically compact.
The three-speed gearbox matches the engine's power output well. There is little unnecessary complexity, and the shaft-drive system gives the motorcycle a level of mechanical sophistication unusual for such a small machine.
The rigid rear frame and cantilever front spring are representative of early-1930s motorcycle engineering. The chassis lacks the sophisticated suspension systems that BMW would introduce later in the decade, but it provides a sturdy and predictable platform for the R2's intended use.
With a top speed of approximately 95 km/h and a relatively low engine output, the R2 is best understood as a practical road motorcycle. Its appeal comes from its engineering character, historical importance, and connection to BMW's transition into the mass market.
The 1931 BMW R2 Series 1 is especially significant because it represents the first production year of BMW's successful lightweight single-cylinder motorcycle program.
Only 4,161 Series 1 motorcycles were produced during 1931, making an original first-year example substantially more historically specific than a later R2 that has been updated or modified during its life.
Originality is particularly important on a Series 1 motorcycle. The exposed valve springs, Sum 19mm carburetor, early controls, electrical components, frame configuration, wheels, fuel tank, mudguards, and other early details should be examined when determining whether an example retains its correct specification.
Matching engine and frame numbers can provide valuable evidence of authenticity, while period registration documents, photographs, service records, dealer records, and restoration documentation can strengthen provenance.
The pressed-steel duplex frame should also be inspected carefully for corrosion, previous repairs, distortion, or modifications. The frame is both a structural component and one of the defining features of the R2's design.
The M67 engine, three-speed gearbox, shaft drive, cantilever front suspension, drum brakes, wheels, and electrical system should all be evaluated when assessing the mechanical condition of a surviving motorcycle.
Because the R2 was an affordable motorcycle intended for everyday transportation, surviving examples may have experienced extensive use or modification. An early example retaining its correct Series 1 components can therefore be particularly valuable to collectors of early BMW motorcycles.
For collectors interested in the origins of BMW's lightweight motorcycle program, the 1931 R2 provides a direct connection to the company's response to the economic conditions of the early 1930s.
The 1931 BMW R2 matters because it marked BMW's return to the single-cylinder motorcycle market and established a successful lightweight motorcycle line during a period of severe economic uncertainty.
Its 198cc engine was deliberately positioned below the 200cc threshold that provided important regulatory and financial advantages in Germany. This helped BMW reach a wider group of customers at a time when its larger motorcycles were becoming increasingly difficult to sell.
Despite its small size, the R2 retained important BMW engineering features, particularly its pressed-steel duplex frame and shaft final drive. These characteristics gave the motorcycle a direct connection to BMW's larger and more prestigious motorcycles.
The R2 also demonstrated BMW's ability to adapt its engineering philosophy to a completely different market segment. Instead of simply producing a low-cost motorcycle, BMW created a lightweight machine that maintained recognizable BMW quality and mechanical sophistication.
The first-year Series 1 is especially important because it represents the original form of the R2 before BMW introduced the successive improvements that would eventually increase output to 8 horsepower.
With 4,161 Series 1 motorcycles produced in 1931, the model was commercially significant while remaining historically rare compared with the much larger production numbers of later R2 versions.
For collectors, the 1931 BMW R2 represents an important chapter in BMW's early motorcycle history: the moment when the company expanded beyond expensive large-capacity motorcycles and developed a machine aimed at a much broader public.
This 1931 BMW R2 represents the first production year of BMW's successful lightweight single-cylinder motorcycle series. Its 198cc M67 overhead-valve engine, pressed-steel duplex frame, three-speed gearbox, shaft final drive, and cantilever front suspension reflect BMW's approach to creating an affordable motorcycle without abandoning the engineering principles of its larger machines.
The Series 1 engine produces 6 horsepower at 3,500 rpm and provides a top speed of approximately 95 km/h. While modest by modern standards, these specifications were appropriate for a motorcycle designed around economical transportation and the regulatory advantages associated with engines below 200cc in early-1930s Germany.
Only 4,161 R2 Series 1 motorcycles were produced during 1931. The first-year configuration is particularly recognizable by its exposed valve springs and original Sum carburetor, making correct specification and originality important considerations for collectors.
The R2 also has an important place in BMW's broader history. The model allowed the company to enter a much larger market for affordable motorcycles during the economic crisis of the early 1930s while retaining characteristic BMW features such as shaft drive and pressed-steel chassis construction.
For collectors, the 1931 BMW R2 offers a rare opportunity to own the earliest production version of an important BMW single-cylinder motorcycle line. Contact us for additional photographs, detailed specifications, frame and engine numbers, service history, originality assessment, provenance, restoration details, and purchasing information for this 1931 BMW R2.
Explore more BMW motorcycles and discover other historically significant BMW machines from the pre-war and classic eras.
The Vintage Motorcycles presents a curated selection of historically significant German vintage motorcycles, with BMW representing one of the most technically influential manufacturers in modern motorcycle engineering. From its early post-World War I developments to the establishment of a distinct mechanical identity, BMW played a central role in redefining structural balance, drivetrain efficiency, and long-distance reliability.
This collection includes machines from BMW alongside other notable German motorcycle manufacturers, each contributing to a tradition of precision engineering and mechanical durability. BMW motorcycles are best understood within the broader context of pre-war motorcycle engineering (1900-1939), particularly during the interwar period when the brand introduced its defining boxer engine and shaft-drive system, as well as through post-war motorcycle development, where these engineering principles were further refined into globally recognized touring platforms.
Each motorcycle within our collection is sourced based on historical provenance, structural originality, and mechanical integrity, ensuring alignment with museum-grade preservation standards. For collectors seeking acquisition opportunities, available machines can be explored through our global vintage motorcycle inventory, supported by a fully insured international shipping service.
BMW engineering is defined by a systematic and highly disciplined approach to mechanical design, emphasizing structural balance, drivetrain efficiency, and long-term reliability. The introduction of the horizontally opposed boxer engine, combined with shaft-drive transmission, established a unique engineering architecture that distinguished BMW from most contemporaries.
From early models such as the R32 to later pre-war and post-war developments, BMW motorcycles illustrate a continuous evolution focused on refinement rather than radical change. This consistency reflects a broader German engineering philosophy, where precision manufacturing, functional design, and mechanical longevity take precedence, positioning BMW as a cornerstone in the study of global motorcycle engineering history.
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