| BMW R51/3 | BMW R 12 |
|---|
| engine specs | |
| Type | |
|---|---|
| air-cooled, four-stroke, boxer twin cylinder, 2 valves per cylinder | Water-cooled, 2-cylinder, four-stroke boxer engine with four valves per cylinder operated by cam followers and two overhead camshafts per cylinder |
| Displacement | |
| 494 cm3 | 1170 cm3 |
| Bore X Stroke | |
| 2.7x2.7 in OR 69 mm | 4.0x2.9 in OR 102 mm |
| Compression Ratio | |
| 6.4:1 | - |
| Horsepower | |
| 24/5800 KW(hp)/RPM | 95/6500 KW(hp)/RPM |
| Torque | |
| - | 81/6000 lb-ft/RPM OR 110/6000 Nm/RPM |
| Fuel System | |
| 2xBing carburetors | - |
| transmission specs | |
| Gearbox | |
|---|---|
| 4-speed, manual | 6-speed |
| Clutch | |
| dry, single plate | - |
| Final Drive | |
| shaft | Shaft |
| chassis specs | |
| Frame | |
|---|---|
| steel | Tubular space frame in steel, engine self-supporting |
| Front Suspension | |
| telescopic fork | USD telescopic forks, 45 mm |
| Rear Suspension | |
| coil compression springs and rubber deflection stops | Aluminium Paralever swinging arm, directly linked WAD spring strut, spring base and rebound damping adjustable |
| Front Brake | |
| 200mm drum | Twin disc brake, floating brake discs, 310 mm, 4-piston monobloc fixed calipers |
| Rear Brake | |
| 200mm drum | Single disc brake, 265 mm, 2-piston floating caliper |
| dimension specs | |
| Overall Length | |
|---|---|
| 83.85 in OR 2130 mm | 86.6 in OR 2200 mm |
| Overall Width | |
| 32 in OR 813 mm | 32.7 in OR 831 mm |
| Seat Height | |
| - | 29.7 in OR 754 mm |
| Weight | |
| 418 lbs OR 190 kg | 500 lbs OR 227 kg |
| Fuel Capacity | |
| 4.5 gallons OR 17.0 L | 3.7 gallons OR 14.0 L |
| Wheelbase | |
| 55 in OR 1397 mm | 59.8 in OR 1519 mm |
| tyres specs | |
| Front | |
|---|---|
| 3.5x19 | 100/90-19 |
| Rear | |
| 3.5x19 | 150/80-16 |
