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BMW R51/2 Specifications

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Start of Production

1950

BMW R51/2

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End of Production

1951

Numbers Produced

5,000

Price

2,750 DM

Engine

 

Internal Designation

254/3

Motor Type

Four-stroke two cylinder flat twin

Bore x Stroke

68 x 68 mm (2.67 x 2.67 in)

Displacement

494 cc

Max Power

24 hp at 5,800 rpm

Compression Ratio

6.4 : 1

Valves

OHV

Carburation System

2 x carburettor type Bing 1/22/39 - 1/22/40

Engine Lubricating System

Forced feed lubrication

Oil Pump

Gear pump

Power Transmission

 

Clutch

Single plate, dry

Number of Gears

4

Shifting

Foot shifting (+ auxiliary manual lever on the gear block)

Gearbox Ratios

3.6 / 2.28 / 1.7 / 1.3

Rear Wheel Ratio

1 : 3.89 (1 : 4.57 with sidecar)

Bevel/Crownwheel

9 / 35 teeth (7 / 32 with sidecar)

Electrical System

 

Ignition System

Battery ignition

Generator

Bosch 6 V/75 W

Spark Plugs

Bosch W 240 T1

Chassis

 

Designation

251/2

Frame

Closed double steel tubular frame

Front wheel suspension

Telescopic fork

Rear wheel suspension

Telescopic suspension

Wheel rims

Deep bed rims

Tyres, Front

3.5 x 19

Tyres, Rear

3.5 x 19

Brakes, Front

Drum brake 200 mm / 7.87 in diameter half hub

Brakes, Rear

Drum brake 200 mm / 7.87 in diameter half hub

Dimensions/Weights

 

Length x Width x Height

2130 x 815 x 720 mm (saddle) ( (83.85 x 32.08 x 28.34 in)

Fuel Tank Capacity

14 litres / 3.07 gal / 3.69 gal US

Unladen Weight with Full Tank

185 Kg / 407 lb

Clearance

120 mm / 4.72 in

Load Rating

400 Kg / 881 lb

Fuel Consumption

4 litres 100 Km approx. / 70 mpg / 58 mpg US

Oil Consumption

1 litre per 1,000 Km approx.

Top Speed

135 Kph / 83 mph

 

 

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