Alder Motorcycles

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Adler M250 1952-1953


Air cooled two-stroke twin, 247cc, B/S 54x54mm
Compression ratio 5.75:1
Amal 20E1B carburettor 1952)
Bing carburetter (1953)
multi-plate clutch in oil bath
two ignition coils

Power: 16 HP @ 5590 rpm

Lubrication: 25:1 petroil mixture.

Fuel consumption: 3.6 litres/100k at 64 km/h


    4 speed with neutral indicator
    Oil capacity: 1.2 litres
    Gearshift lever on left side of engine
    Shift pattern: 4 up - neutral, 1st, 2nd, 3rd, 4th.
    1st gear = 2.80:1
    2nd gear = 1.53:1
    3rd gear = 1.11:1
    4th gear = 0.81:1
    primary drive = 3.44:1
    final drive = 2.0:1 (solo), 2.25:1 (sidecar)
    NB: All MB/MBS models have same gearbox and gear ratios.

Max speed: 116.5 km/h

Weight: 135 kg (1952) 145 kg (1953)

Wheels: 1.85 x 16" steel rims, 36 spokes

Brakes: 180mm x 30mm.

Tyres: 3.25x 16" front and rear.

Maximum all-up weight without sidecar: 295 kg; with sidecar: 420 kg

Frame: double cradle steel tube with sidecar attachment points.

Fuel tank: rubber mounted 12 litre with 3 litre reserve.

Front suspension: leading link with integral damping.

Rear suspension: telescopic hydraulic spring dampers.

Electrical system: 6 volt 60 watt dynamo, voltage regulated,

Steering lock.

Lockable toolbox.

Adjustable steering damper.

Enclosed rear chain.

Folding rear guard.

Dual mufflers, low pipes.