Alder Motorcycles

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Adler MB250 1954-1956


Air cooled two-stroke twin, 247cc, B/S 54x54mm
Compression ratio 5.75:1
Bing 1/22/72 carburettor
multi-plate clutch in oil bath
two ignition coils

Power: 16 HP @ 5600 rpm

Lubrication: 25:1 petroil mixture.

Fuel consumption: 3.56 litres/100k at 80 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: 117 km/h

Weight: 145 kg

Wheels: 1.85 x 16" steel rims with 36 spokes, alloy hubs.

Brakes: 180mm x 30mm.

Tyres: 3.25 x 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 15 litre with 3 litre reserve.

Rear suspension: hydraulic spring dampers.

Front suspension: leading link with integral damping.

Electrical system: 6 volt 90 watt dynamo, voltage controlled

Steering lock.

Lockable toolbox.
Adjustable steering damper.
Enclosed rear chain.
Folding rear guard.
Dual exhausts, mufflers with removable baffles .