| Attribute | Specification |
|---|---|
| Production Years | 1948 – 1950 |
| Engine Type | Single-cylinder OHV, 247cc |
| Oil Capacity | 1.25 L (SAE 20W-50 or SAE 50) |
| Tire Size (F/R) | 3.25 x 19 / 3.25 x 19 |
| Tire Pressure (F/R) | 1.2 bar (17.4 psi) / 1.5 bar (21.7 psi) |
| Electrical System | 6V 7Ah Battery |
| Spark Plug | Bosch W 240 T 1 (Modern: NGK B8HS) |
The BMW R 24 (Internal Code 0224/1) holds a sacred place in motorcycling history as the first machine produced by BMW after World War II. While it visually resembled the pre-war R 23, it introduced a revolutionary engineering milestone: it was the first BMW single-cylinder motorcycle to feature a four-speed gearbox, providing significantly better torque management and cruising capabilities than its predecessors.
Engineering Overview
Developed under the constraints of Allied restrictions, which initially prohibited BMW from producing large-capacity engines, the R 24 was limited to a 250cc displacement. However, the engineers at MotoSpecsLab identify the R 24 as a masterpiece of efficiency. The 12-horsepower OHV engine utilized a centrifugal spark advance, a sophisticated feature for the era that ensured smoother idling and improved acceleration.
Maintenance Essentials
Lubrication System
For the air-cooled single, thermal management is critical. We recommend using a high-quality SAE 50 Monograde for vintage operation in warm climates, or a 20W-50 for more versatile temperature ranges. The sump capacity is exactly 1.25 liters. Given the absence of a modern oil filter, frequent changes (every 1,000–1,500 miles) are mandatory to prevent sludge buildup.
Ignition and Electrical
The 6V system is powered by a 7Ah battery. Timing is everything on these machines. The original Bosch W 240 T 1 plugs are increasingly rare; the modern equivalent is the NGK B8HS or Bosch W4AC. Ensure the gap is set to 0.6mm (0.024 inches) for optimal combustion.
Chassis and Tires
The R 24 utilizes a rigid rear frame, making tire pressure the primary source of ‘suspension’ dampening. Maintaining the front at 1.2 bar (17.4 psi) and the rear at 1.5 bar (21.7 psi) is essential for both handling and protecting the 19-inch rims from impact damage. The 3.25 x 19 square-profile tires provide the period-correct contact patch required for the R 24’s geometry.
MotoSpecsLab Verdict
The BMW R 24 is more than a vintage motorcycle; it is a testament to resilience. From a technical perspective, its simplicity is its greatest strength, provided the owner adheres to strict maintenance intervals regarding lubrication and ignition timing. For the modern collector, it represents the purest form of post-war German engineering.