| Feature | Specification |
|---|---|
| Model Code | 0252/3 |
| Production Years | 1960-1962 |
| Engine Oil | 20W-50 Mineral (2.0 L) |
| Tire Size | F: 3.50 x 18 / R: 3.50 x 18 |
| Tire Pressure | F: 1.8 bar / R: 2.1-2.5 bar |
| Battery | 6N11A-1B (6V) |
| Spark Plug | NGK B8HS / Bosch W3AC |
The BMW R 50 S remains one of the most enigmatic and sought-after machines in the marque’s post-war history. While many enthusiasts gravitate toward the R 69 S, the R 50 S is actually the rarer machine, with only 1,634 units produced during its brief three-year production run. Its unique engineering highlight was the implementation of a high-compression (9.2:1) 500cc engine, which allowed it to reach a top speed of nearly 160 km/h, a remarkable feat for its displacement at the time.
Engineering and Performance
The ‘S’ in the R 50 S designation stands for ‘Sport,’ and the engineering reflected this. Unlike the standard R 50, the S-model featured Bing 1/26/75-76 carburetors and a hydraulic steering damper as standard equipment. This was a motorcycle designed for the burgeoning autobahn culture of West Germany, offering a blend of high-revving performance and the legendary reliability of the Earles-fork chassis.
Maintenance Guidelines
Lubrication System
For the 0252/3 engine, the use of modern synthetic oils is generally discouraged by the MotoSpecsLab team. We recommend a high-quality 20W-50 Mineral oil. The 2.0-liter capacity ensures adequate cooling and lubrication for the internal slingers. Given that these engines lack a modern spin-on filter, frequent oil changes (every 2,000 to 3,000 miles) are critical to prevent sludge buildup.
Electrical and Ignition
The R 50 S utilizes a 6-volt electrical system powered by a 6N11A-1B battery. For optimal combustion, we specify the NGK B8HS or Bosch W3AC spark plugs. These colder heat-range plugs are essential to handle the higher operating temperatures generated by the 9.2:1 compression ratio.
Chassis and Tires
The handling characteristics of the R 50 S are heavily dependent on tire pressure and condition. Both front and rear utilize 3.50 x 18 tires. For solo riding, maintain 1.8 bar (26 psi) in the front and 2.1 bar (30 psi) in the rear. If carrying a passenger (Duo), the rear pressure must be increased to 2.5 bar (36 psi) to maintain stability and prevent sidewall overheating.
Editorial Verdict
The BMW R 50 S is a masterpiece of transition—a bridge between the utilitarian workhorses of the 1950s and the high-performance sport bikes of the 1970s. While maintenance requires a diligent eye on the 6V system and mineral oil levels, the reward is an unparalleled vintage riding experience that is as mechanically satisfying as it is historically significant.