Adler MB 250 RS


Make Model.

Adler MB 250 RS




2 cylinder, 2 stroke, flat-crowned pistons


247 cc / 15.1 cub in.

Bore x Stroke

54 x 54 mm


Air cooled


Petrol oil mix 25:1


Multi plate


Kick start


6V, 6Ah


Bosch coil


Twin Bing carburetors

Exhaust System

Twin, steel, chrome

Max Power

19.2 kW / 26 hp @ 7500 rpm

Compression Ratio

1: 5.75


Multi disc


4 Speed gearbox housed in engine block, foot gearchange

Final Drive



Double tubular frame with sidecar adapter.

Front suspension

Twin swinging leading link forks with shock absorber and steering damper

Rear suspension

Swinging fork adjustable for load and road conditions

Tyres (front and back)

3.25 x 16 in.

Brakes (front and back)

Drums, 180 mm diameter


1257 mm / 49.5 in.

Dry Weight

98 kg / 216 lbs

Fuel Capacity

12 L / 3.2 US gal


3.8 L / 1 US gal

Average Consumption

3.6 l/100 km / 27.8 km/l / 65.3 US mpg

Top Speed

169 km/h / 105 mph


Metal Green


In 1949, Adler was one of the first German marques to recommence production after the war. Right up to end of manufacture in 1957, it remained unapproachable as a maker of two strokes. Late in 1952, Adler unveiled the MB 250, a tw0 stroke twin which quickly became known as the "Cannonball." It was equally successful as a touring bike, a sports bike and an off roader. But it was particularly successful under another name, for the first Yamaha twin (the YD 1 of 1957) was more or less a direct copy of the Adler MB and the subsequent Yamaha twins have followed its pattern.

A Fabulous Two Stroke Twin
Soon the touring MB 250 was joined by the sporting 250 S, then by a racing version, the 250 RS with twin carburetors and swinging fork rear suspension instead of plungers. The 250 RS of 1954, still air cooled, developed 26 hp @ 7500 rpm, weighted 216 lb and was capable of more than 105 mph. Highly prized in its native Germany, the Adler RS enjoyed a rare foreign success in France's Bol d'Or in 1954, where a solo RS and another with a side car won their respective under 350cc categories.

Adler takes to Water
Beginning in 1954, tuner/rider Hellmut Hallmeier perfected a water cooled 250 RS, whose highly successful racing career continued into the sixties. The last "works" RS Adlers ridden by Walter Vogel and Hellmut Hallmeier developed 39 hp at over 10,000 rpm with a top speed of 125 mph.