DKW

DKW 1919 - 1970's Danish engineer Jörgen Skafte Rasmussen was the originator of the DKW based in Zschopau, Germany. Designing a steam powered engine for a light steam car, which was produced in 1916 and then in 1919 started production with a small 2 stroke engine which clipped onto a conventional bicycle driving the back wheel by means of a leather belt.

Dampf Kraft Wagen (Steam powered vehicle)
Der Kadett Wunsche (The Schoolboys Dream)
Das Kleine Wunder (The Little Miracle)

The first and most likely derivative of DKW, Dampf Kraft Wagen (Steam powered vehicle) came from the earliest manufacturing days. The term of Das Kleine Wunder (The little miracle) has been attributed to a small car designed in 1928 and the term Der Kadett Wunsche (The Schoolboys Dream) either to the racing success of small motorcycles between the wars or a small engine of 18 cm3 to animate scientific toys.

Production of DKW motorcycles started in 1922 and by 1928 their success led to DKW being the largest motor bike factory of the world producing over 60,000 machines a year, giving the company the ability to produce its first car with front wheel drive in that year.

Jörgen Rasmussen was innovative and came up with many fresh ideas. 1924 saw the introduction of the SM (Steel Model) model with 173cc engine and innovative Pressed Steel Frame, which has been copied by many other manufacturers. 1931 saw the Schürle patent enabling inverted scavenging (designed by Ing Schnuerle) and also a removable aluminium cylinder head for better cooling was introduced and in the racing world considerable success was gained by the split single design of Hermann Weber who died after the war in Soviet Russia. This was followed in 1932 by the firm becoming part of the Auto-Union combine and continued building cars and bikes until the war. The Auto-Union founded in Saxony consisted of DKW (Zschopau), Wanderer (Chemnitz), AUDI and Horch (Zwickau) with the trademark of four connected rings denoting the four companies. In 1938 Ewald Klüge became the first German to win the Isle of Man TT.

During the war years DKW produced the RT125 a lightweight motorcycle with a unit construction two stroke engine housing a three speed gearbox, the design for which was captured by the allies and the BSA Bantam, Harley Davidson Hummer, Moska 125 and eventually the Yamaha YA1 are all derivatives of this outstanding bike.

After the World War II with the partition of Germany by the allied powers, the DKW Company sat in the Soviet controlled eastern sector.

Post-war production began again in 1949 in the newly formed GDR in the factory at Zschopau under the brand name IFA-DKW and in 1956 the trademark MZ (Motorradwerk Zschopau) is introduced. Up to the German reunification in 1989, 80,000 motorcycles were produced on a yearly basis and were exported to over 100 countries. In the western sector DKW commenced production in 1949 but at the new headquarters in Ingolstadt on the Danube in Bavaria with the RT125 that now incorporated swinging rear suspension using coil springs housed in the fork blade and in 1951 a tele-forked version was introduced.

Equally outstanding 200cc, 250cc and 350cc machines of similar design using twin cylinder 2 stroke engines followed this. 1956 saw the introduction of Earles Forks denoted by VS. A moped called The Hummel (Bumble Bee) was produced between 1956 - 1959 and a 75cc scooter called Hobby between 1954 to 1957. But in 1958 independent production came to an end as the company came under the control of Daimler-Benz in 1958 when they bought the majority of Auto Union and motorcycle production was amalgamated into the Zweirad Union with Victoria and Express, the Victoria factory at Nurnburg being the headquarters although the Ingolstadt factory was retained. In1966 the Zweirad Union was sold to Fichtel & Sachs ("Hercules"), and this gave the DKW name a new lease of life as it was used to sell Hercules motorcycles into England and the USA as Raleigh cycles sold bicycles under Hercules brand name.

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1949 RT125W 123cc	1953 RT250H 244cc	1954 RT125/2H 123cc	1955 Hobby Luxus 74cc
1955 RT175 174cc	1955 RT350 348cc	1956 Hummel Luxus 48cc	1957 RT125/2H 123cc
1957 RT175VS 174cc	1958 Hummel Luxus 48cc	1964 Violetta 48cc	1965 Hummel Type 155 48cc
1970 TS159 49cc	1973 RT125E 125cc	1975 W2000 294cc Wankel

DKW Bike Review - Road Models

RT125 1947-56, 122cc, 2-stroke single, 3 speed, 150lb, 47mph
Initially produced during the War years it was captured by the allied armies and copied in the UK as the BSA Bantam, USA as the Harley Hummer, Russia as the Moska 125 and even the Yamaha YA1 was based on this model. Rigid frame with box section spine and single front down tube, front forks were of girder construction and single saddle made this a utility model. 1951 telescopic forks added. 1954 plunger rear suspension.

RT175 1954-59, 174cc, 2-stroke single, 4 speed
Based on the RT200 engine and the RT250/1 chassis. 1955 a sport version was introduced with more power, new front forks and swinging arm rear suspension denoted by the suffix S on the model. Dual seat option available. Introduction of Telves Interrupted Finning on the cylinder barrel. 1956 the VS model with Earles front forks and a new headlamp cowing were introduced.

RT200 1951-59, 191cc, 2-stroke single, 4 speed, 255lb, 57mph
Based loosely on the RT125 but with a rigid frame and telescopic front forks being a backward step. 1953 plunger suspension added. 1955 a sport version was introduced with more power, new front forks and swinging arm rear suspension denoted by the suffix S on the model. Dual seat option available. Introduction of Telves Interrupted Finning on the cylinder barrel. 1956 the VS model with Earles front forks and a new headlamp cowing were introduced.

RT250 1952-59, 244cc, 2-stroke single, 3 speed (1952-53), 4 speed, 75mph
Larger version of the RT200. 1954 the RT250/1 model came with 4 speed box and more power replacing the RT250. 1955 RT250/2 with new front forks and a face lift with an increase in power. Dual seat option available. Introduction of Telves Interrupted Finning on the cylinder barrel. 1956 the S model was introduced with improved performance, which replaced the RT250/2. Also the VS model with Earles front forks and a new headlamp cowing were introduced.

RT350 1954-59, 348cc, 2-stroke twin, 4 speed, 78mph
A handsome well equipped model with good performance and exceptional finish. Tubular frame with plunger rear suspension and telescopic front forks. The rear brake was hydraulic. Good acceleration with relatively low top speed and sumptuous suspension. 1955 Swinging arm rear suspension and full width hubs became the RT350S. Introduction of Telves Interrupted Finning on the cylinder barrel.

Hobby 1954-57, 74cc, 2-stroke single, automatic, 139mpg, 40mph
An innovative designed scooter with centrifugal expanding pulley drive, hand pull-cord starter, automatic petrol/oil mixture, tele front suspension and pivoted rubber sprung rear fork. Looking like a full size scooter it was offered in standard or deluxe (Luxus), which had full width front brake, dual seat and additional chrome plating.

Hummel 1956-59, 48cc, 2-stroke single
Hummel meaning Bumble Bee was a small capacity moped. The deluxe model (Luxus) with dual seat and larger fuel tank was also available.

W2000 1970-75, 294cc (882cc) Wankel 4-stroke, 6 speed, 27bhp, 90mph, 27mpg.
The Hercules/Sachs W2000 was sold as the DKW for the UK market from 1974. Sachs were one of the first licensees of the Wankel engine developed by NSU & used the 294cc air-cooled version of the rotary engine for the W2000, which the FIM deemed to be 588cc, although normally seen as a 882cc as the Wankel engine has three cycles of 294cc per revolution. First shown in 1970 the W2000 entered full production in 1974. Only 1784 units were sold. A well handling bike with no vibration. 12 volt electrics and good VDO clocks. Engine noise evident at low revs and gearbox 5th & 6th too high ratio providing over-drive in top. The first 1145 engines used a petroil fuel mixture, but a separate oil injection system made by Mikuni of Japan fitted to the later 639 engine units. Cost £919 when launched at the Hilton Hotel in September 1974. High fuel consumption of 27mpg is a downside of the engine which also burns two-stroke oil making it an air polluter. Hercules/Sachs W2000

Other models were sold with the DKW badge, but manufactured as part of the Zweirad Union from 1960.

Telves System

The process was pioneered by Alfred Telves of Frankfurt-am-Main in an endeavour to obtain more efficient heat dissipation, allowing higher engine speeds and greater power output.

This system was not exclusive to DKW but they were the ones who made most use of it on their production bikes. The process is based upon a centrifugal casting method, producing bi-metal cylinders consisting of thin staggered copper fins on a cast iron cylinder barrel. This was achieved as the centrifugal process threw the molten copper being the heavier metal into the extremities forming the fins, while the lighter molten grey iron formed in the centre area, creating the cylinder wall.

The advantage of this system was to produce a cylinder barrel which dissipated the heat more efficiently from the thin copper fins. The fins could be made shorter and closer together, which were staggered to increase the air flow efficiency. This would not be possible to achieve with cast iron alone and led many manufacturers to concentrate on aluminium from the sixties onwards for their production models. The other benefit was a reduction in noise levels.