The BMW R51 motorcycle specifications include a 494 cc (30.14 cu in) engine, power of 24.1 hp (17.6 kW) @ 5,600 rpm, a 4-speed gearbox, and a listed weight of 182 kg (401.2 lb).
Key specifications
Year-specific specification changes
How the BMW R51 compares
This compares the motorcycle with all BMW models in this specifications database. The blue marker is this model and the grey line is the BMW database average.
About 70% lower than the BMW database average. Around the 10th percentile across BMW models.
About 46% lower than the BMW database average. Around the 13th percentile across BMW models.
About 20% lighter than the BMW database average. Around the 12th percentile across BMW models.
About 27% smaller than the BMW database average. Around the 15th percentile across BMW models.
BMW database percentile rankings
Percentiles show where this motorcycle sits across the BMW specifications database. They are descriptive database rankings, not performance ratings.
24.1 hp — more powerful than about 10% of BMW models with power data.
494 cc — larger displacement than about 13% of BMW models.
182 kg — heavier than about 12% of BMW models, or lighter than about 88%.
14 L — larger than about 15% of BMW fuel tanks in this database.
Dimensions compared with BMW average
Each measurement is compared with the average value across BMW models where that dimension is available.
2,130
2,193
Close to average.
815
877
7% below average.
960
1,199
20% below average.
1,400
1,497
6% below average.
Mechanical overview
Additional useful specifications
| Front tire size | 3.50-19.00 |
|---|---|
| Rear tire size | 3.50-19.00 |
| Estimated theoretical fuel range | 350 km |
| Power-to-weight ratio | 0.132 hp/kg |
| Power-to-weight | 132.4 hp/tonne |
| Specific power | 48.8 hp/L |
| Bore/stroke ratio | 1.00:1 (Square) |
Model information
| Category | Allround |
|---|
Engine specifications
| Engine type | Two cylinder boxer, four-stroke |
|---|---|
| Displacement | 494 cc (30.14 cu in) |
| Power | 24.1 hp (17.6 kW) @ 5,600 rpm |
| Bore × stroke | 68.0 x 68 mm (2.7 x 2.7 inches) |
| Compression ratio | 6.7:1 |
| Cooling system | Air |
| Fuel system | Carburettor. Amal |
| Fuel control | Overhead Valves (OHV) |
| Ignition | Battery |
| Starter | Kick |
| Lubrication | Wet sump |
Transmission and drivetrain
| Gearbox | 4-speed |
|---|---|
| Final drive | Shaft drive (cardan) (final drive) |
| Clutch | Dry-single plate-cable operated |
Chassis and suspension
| Frame | Steel single cradle |
|---|---|
| Front suspension | Cartridge |
| Rear suspension | Twin shock-Swingarm |
Brakes, wheels and tires
| Front brakes | Expanding brake (drum brake) |
|---|---|
| Rear brakes | Expanding brake (drum brake) |
| Front tire | 3.50-19.00 |
| Rear tire | 3.50-19.00 |
Dimensions and weight
| Wet weight | 182 kg (401.2 lb) |
|---|---|
| Overall length | 2,130 mm (83.9 inches) |
| Overall width | 815 mm (32.1 inches) |
| Overall height | 960 mm (37.8 inches) |
| Wheelbase | 1,400 mm (55.1 inches) |
| Carrying capacity | 210kg |
Fuel and emissions
| Fuel capacity | 14.00 L (3.70 US gal) |
|---|---|
| Fuel consumption | 4.00 L/100 km (25.0 km/l or 58.81 mpg) |
| Greenhouse gases | 92.8 CO 2 g/km. (CO2 – Carbon dioxide emission) |
Performance
| Top speed | 140.0 km/h (87.0 mph) |
|---|
Electrical and instruments
| Battery | Lubrication system |
|---|
Other specifications
| Seat | Single seat |
|---|
Disclaimer: Specifications may vary by market, trim, production date and optional equipment, and scraped or historical data can contain errors. Comparison and percentile values are calculated from BMW models in this specifications database. Always double-check important specifications against the motorcycle owner’s/service manual and official BMW information before relying on them. Visit the official BMW website.