DKW GB250 1

DKW has always been ahead in the design of 250 c. c. motorcycles. In 1927 the factory introduced thefirst E 250. Since then many hundreds of thousands of ma-chines of this size have been built and a number of international races and world championships have been won.

Looking backto-day on the development sińce 1927 onecan clear-ly see two vitally important factors: Firstly, the traditional princi-ple to buildslow-rewing, economical and sturdy DKW two-stroke engines, and secondly, the endeavour steadily to increase the performance and the speed of the machines.

Surely it would have been easier simply to trim up the engines, a method which would undoubtedly have produced morę power and a higher top speed. But what is the good of such deve-lopment if it is combined with a reduction in economy, reliability and resistance to wear? DKW was convinced that on the basis of its traditional development and research work it would obtain equal and even better results than by simple "trimming," because one knew very well that there was still much to be expected in the way of performance from the two-stroke engine. Since 1927, for example, the performance of the 250 c. c. class has been increased from 6.5 BHP on the E250 to 14.1 BHP on the new RT250 with practically no increase in engine speeds. The maximum road speed of the motorcycle has been increased by approximately 50%.

Could there be a better argument for proved design of this new model? The development of performance was aided considerably by the new-ly designed intake- and exhaust-

silencers, both units being in perfect tune with each other. Furthermore, an additional advantage was gained by these new silencers as they madę it possible to reduce the exhaust noises to such an extent that one can describe this new DKW as a remark-ably quiet motorcycle.

The 4-speed gearbox is exactly tuned in its gear ratios to the engine performance. It meets all practical demands and enables -together with the "over-revving" capacity of the DKW two-stroke engine - astonishingly high cruisingly speeds. For example one can accelerate with perfect ease up to 18,6 m.p.h. in lst gear gear, in the second up to nearly 37,3 m.p.h. and in the third even up to 49,7 m.p.h., and can then shift in to fourth without any no-ticeable reduction in speed. From a standing start the machinę ac-celerates up to 56 m.p.h. in only 18 seconds, the maximum being 71 m.p.h. Naturallythe new RT250isespeciallysuitableforsidecar use. This is madę possible by 14.1 BHP, the sidecar-tuned suspens-ion, the closed, rigid Steel tubę frame and the excellently gratuat-ed gearbox. But seemingly smali details have also been considered on the new DKW: The exhaust pipę is placed on the leff-hand side so as to remove it as far as possible from the sidecar, an advantage which the sidecar passenger will gratefully appreciate. The des-cription of this new DKW would, however, be incomplete if we failed to refer to the legendary economy of all DKW motorcycles, a feature which has been proved by hundreds of thousands of machines all over the world. It was also a fundamental principle, when designing the new RT 250, to build a machinę that could be maintained by motorcycle enthusiasts of the most moderate means. So much forthetechnical qualitiesof the RT 250. Two other features however, should not be forgotten: The smart oppearance due to the elegant flowing lines and the remarkable silence of the machinę which is scarcely louder than that of a motorcar. Such ad-vantageswill always find the convinced approval of all motorcycle enthusiasts, and last but not least, also that ®f his passenger.

DKW RT

The development of the 250 c.c. motorcycles

E 250

E 250 ⁷M"^P

ri

year 1927

RT 250 14.LBHP

RT 250

RT 250 11JUHP

SB, NZ 250 9 BHP

1929    1934/41    1951

1953    1953/54

14.1 BHP, 4700 r. p. m.

Normal consumption 88'/^ m.p.g.

Maximum speed 71 m.p.h.

The design of the DKW two-stroke engine could not be simpler. Piston, connecting rod and cranks-haft are the only moving parts. Notę the crankshaft with fuli counterweights and three bear-ings; also the generator shown in the exploded view.

The new four-speed gearbox guarantees perfect power transmission withln the entife speed raige.