BMW R51/3
The BMW R51/3 was BMW's second post-World War II 500 cc motorcycle, following the briefly produced R51/2. It featured a flat-twin engine and exposed drive shaft.[1] In 1951, the R51/3 succeeded and modernized the 1950 R51/2, which was essentially a pre-war design that was produced after the war. The 600 cc R67, R67/2, and R67/3 series and the more sporting R68 model also followed the R51/2.
History
Following World War II, Germany was precluded from producing motorcycles of any sort by the Allies. When the ban was lifted, in Allied-controlled Western Germany, BMW had to start from scratch. There were no plans, blueprints, or schematic drawings. Company engineers had to use surviving pre-war motorcycles to create new plans. In 1948, it introduced the 250 cc R24, which was essentially a pre-war R23, complete with rigid rear end.
When larger machines were permitted, BMW introduced its R51/2 in 1950, a model that was in production for only one year and that was essentially a pre-war BMW produced after the war. The R51/3 was then introduced in 1951 for a production run of four years.
The 600 cc R67, sister model to the R51/3 and almost identical visually, was also introduced in 1951, but it went through two revisions. The more powerful R67/2 came out one year later and was replaced in 1955 by the R67/3, which was in production through the 1956 model year.
In 1952, BMW introduced the 600 cc R68,[2] which produced 35 hp (26 kW), had a compression ratio of 8.0:1.
Technical data
| R51/3 | R67 - R67/3 | |
|---|---|---|
| Design | Boxer Flat Twin | |
| Engine | Four-stroke OHV | |
| Model Years | 1951–1955 | 1951–1956 |
| Bore | 68 mm / 2.68 in | 72 mm / 2.83 in |
| Stroke | 68 mm / 2.68 in | 73 mm / 2.87 in |
| Displacement | 494 cc (30.1 cu in) | 594 cc (36.2 cu in) |
| Power | 24 hp (18 kW) @ 5800 rpm | 26 hp (19 kW) / 28 hp (21 kW) @ 5500 rpm |
| Compression Ratio | 6.3:1 | 5.6:1 / 6.5:1 |
| Top Speed | 140 km/h (87 mph) | 150 km/h (93 mph) |
| Curb Weight | 190 kg (419 lb) | |
| Gross Vehicle Weight | 355 kg (783 lb) | |
| Fuel Tank Capacity | 17 L (3.7 imp gal; 4.5 US gal) | |
See also
References
External links
Media related to Lua error in package.lua at line 80: module 'strict' not found. at Wikimedia Commons
