DKW SS 250
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The DKW SS 250 (SS = Supersport) was a motorcycle model that Auto Union built at the DKW plant in Zschopau from 1935 to 1939 and developed from a sporty touring motorcycle or " sports tourer " to a racing machine for private drivers. These "production racers", as they would later probably have been called, had a water-cooled single-cylinder two-stroke engine with double pistons and a charge pump ; Cubic capacity 250 cm³. Around 200 DKW SS 250 were manufactured and sold in total.
Model history and technology
Years of construction 1935 to 1937
The engine of the first DKW SS 250 with a light metal cylinder head, front-mounted charge pump and two carburetors between the exhaust pipes attached to the rear of the cylinder developed 20 hp (15 kW) at 4800 rpm. That was about twice the performance of the touring motorcycles of the time with a displacement of 250 cc. At the beginning of the construction period, the SS 250 had a three-speed gearbox. Shifting was done either with a manual gear lever on the right of the tank or with a rocker switch . The pressed steel profile frame and the trapezoidal fork with closed sheaths corresponded to those of the series model SB 500. There was no rear suspension.
It was with machines like this that DKW works drivers Arthur Geiss , Walfried Winkler and Ewald Kluge won the silver vase at the 17th International Six-Day Tour in 1935.
In 1936, too, the SS 250 was initially supplied with the pressed steel profile frame, which was, however, replaced by a double tube frame with a narrower fork in the course of the year. In connection with this, the wheels were no longer 19 inches, but 21 inches. The previously divided cooler ( thermosiphon ) was installed between the front frame tubes. From then on, the cylinder head and water hood of the cylinder were separate, as with the factory machines. The engine output rose to around 22 hp at 4800 rpm.
In 1937 the SS 250 was further adapted to the factory machines, received a large tank and the original racing fork made of thin tubes.
Model 1938/39
The end of 1937 the motorcycle received a rear suspension with swingarm by Benelli -type. At the end of the frame tubes, guide cylinders with the springs were welded almost vertically, in which the end pieces of the swing arms were mounted. A four-speed racing gearbox with footshift was installed separately and no longer integrated into a block engine . The previous Kickstarter was omitted. In the last version, the cooler was no longer inclined forward, but installed vertically in order to shift the center of gravity to the rear. The front full-hub brakes were also new. The maximum speed of the machine, which weighs around 120 kg without petrol, was 140 km / h.
Quite a few DKW SS 250s as well as some of the 50 or so DKW SS 350s from 1939 survived the war and were again driven in races from 1947 to 1950.
Technical specifications
| DKW | SS 250 (1939) |
|---|---|
| engine | Two-stroke, single-cylinder, double-piston engine |
| Displacement | 243 cc |
| Bore × stroke (2 times) | 47.5 x 68.5 mm |
| Power at 1 / min | about 20 hp (about 15 kW) at 5000 |
| Carburetor | 2 Amal 15 TT 35, installed behind the cylinder |
| ignition | Flywheel magneto |
| cooling | water |
| lubrication | Fuel-oil mixture 1:15 (recommended as fuel: petrol- benzene 50:50) |
| transmission | 4-speed gearbox with foot shift (gear lever on the right) |
| Power transmission | Duplex chain in closed light metal housing |
| frame | Welded tubular steel frame, trapezoidal fork with shock and steering damper, handlebars in rubber |
| Rear suspension | Swing arm, springs in guide tubes |
| wheelbase | 1350 mm |
| overall length | 2100 mm |
| Saddle height | 720 mm |
| Empty weight (ready to drive) | approx. 140 kg |
| Tank capacity | approx. 20 l |
Web links
Individual evidence
- ^ Motorsport history . Retrieved October 12, 2019.
Literature and source
- Siegfried Rauch : DKW - The story of a global brand . 3rd edition, Motorbuch Verlag, Stuttgart 1988, ISBN 3-87943-759-9 , pp. 98-103.