.

BMW R 51

Make Model

BMW R 51

Year

1938 - 40

Engine

Four stroke, two cylinder horizontally opposed Boxer, pushrod operated 2 valves per cylinder.

Capacity

494 cc / 30.1 cu in.
Bore x Stroke 68 x 68 mm
Compression Ratio

6.7:1

Cooling System Air cooled

Induction

2 x Amal 5/423 carburetors

Ignition

Battery ignition

Starting

Kick

Clutch Single plate, dry

Max Power

18 kW / 24 hp @ 5800 rpm

Transmission

4 Speed

Final Drive

Shaft
Gear Ratio 1st 3.60 / 2nd 2.28 / 3rd 1.70 / 4th 1.30:1
Frame Closed double loop steel tubular frame

Front Suspension

Telescopic fork

Rear Suspension

Long swing arm with suspension units and oil pressure shock absorbers

Front Brakes

∅200mm Drum, duplex full hub

Rear Brakes

∅200mm Drum, simplex full hub

Front Tyre

3.50 -19"

Rear Tyre

3.50 -19"

Wet-Weight

182 kg / 400 lbs

Fuel Capacity 

14 liters / 3.60 US gal