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ESO Scramblers, ESO/Jawa Speedway & Ice Racing Motorcycles

ESO (From "Evergreen Jawa 1929-1989" by Jan Kralik)

The popularity and success of Jawa in speedway racing dates back to prewar times. However, after World War II the make was not engaged in speedway motorcycle production, so mostly British JAP machines were used for speedway in Czechoslovakia. It had not been exceptional that some riders were successful in two or three kinds of the motorcycle sport, and this was the case of Vaclav Stanislav and Jaroslav Simandl, weather-beaten old wolves from the 1930's. They were not idle during the War either, taking part in the development of the new machines as had been mentioned. No wonder they went back to their beloved sport after the War.

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Their story which began quite innocently while waiting for a ship at Dover, had for them as well as for the Czechoslovak sport, rather unexpected and incredible consequences. The two were returning as participants in the 1949 ISDT in Great Britain. Stanislav had bought in London a connecting rod for his speedway JAP, but needed a camshaft as well. And would J. Simandl lend him the money, he would look for it in France as he had not enough to pay for it. Simandl was of course pulling his old pal's leg saying he should not worry, because he would make him a complete engine when they got back to Czechoslovakia. On board they betted the camshaft, on the way across France a complete engine. Simandl swore that he would construct a single cylinder better than the famous JAP.

When a chap makes a promise, he should keep his word, which Simandl wanted, but it was difficult. Of course Stanislav kept bothering him so much that he saw no other way out than to make parts for a total of eight engines which were copies of the JAP design. Four he assembled, the other four were left for spare parts.

The engines were divided between his pals, Stanislav, Marha, Eman, & Holub. Stanislav took away the very first and instead of JAP, he had "Jitka", the name of his newly born daughter engraved on the engine. Marha wanted to have on it his name "Eman" engraves on his engine, and Holub, (Czech for pigeon) wanted the symbol of a pigeon on his engine. Simandl kept the fourth engine for himself. It seemed that the small toolmaker's shop where Simandl worked, was well rid of the engines.

But word of Simandl's engine soon spread, and the Sports Commission of the Automobile Club of that time urged Simandl to build more engines. Then Motokov, the foreign trade organization, wanted to put the engine on display at a motorcycle show in Sweden, so Simandl gave in. All he worried about was that the Swedes would give preference to the original JAP rather than his copy, so he decided to make his own engine surpassing the JAP. After all, the design of the English engine was 20 years old. So Simandl designed a new short stroke single cylinder engine. He placed an order with his own firm to cover the production, he paid himself 28,000 Crowns for it. The engine was installed it in a road racing motorcycle frame which his son Jiri started to race and develop. In a workshop with 18 employees there was of course no dynamometer.

The single cylinder appeared to be a success, later measurements revealed that it's output was 45 hp, and so it was called "S-45". The first four speedway machines were sold to the German Democratic Republic, bearing the mark ESO which came into being in a very simple way. In the end the letter "S" was painted in red on the tank, hence ESO (ace in Czech).

At the Divisov workshop speedway racing motorcycles started to be made in larger numbers to displace on the European tracks the JAP engines. Simandl had kept his word.

In the early 1950's ESO was nationalized, Jaroslav Simandl continued to be the leading figure. In January 1964, the plant became part of the Jawa Corporation. Since then, the world famous speedway racing motorcycles have carried the Jawa name.

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1950 ESO Road Racer. This bike featured one of the first Simandl built
engines, one of the JAP copies. This picture courtesy Tony Skach.

The factory that built ESO motorcycles still exists today in Divisov, Czech Republic. This factory has built speedway and ice racing motorcycles under the Jawa name since 1964. Click here to visit the web site of "Jawa Divisov, a.s." (the Jawa Speedway Factory).

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1955 ESO 350 Scramblers

Shown at right are two works 350cc ESO scramblers at the Sarka moto-cross in 1955. These motorcycles were developed from the road racing motorcycles that were first used to test the ESO unit construction 4-stroke engine. These early ESO scramblers were not much more that road racing bikes with knobby tires mounted, as you can see from the picture. The bikes had 100mm (4 inches) of suspension travel, front & rear. Picture from Svet Motoru 1955. Scans from Svet Motoru courtesy Mario Mager

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1956 ESO 500 MC

At left is the 1956 ESO 500 Moto-cross. Further development of the moto-cross models included telescopic forks, high front fender, and ergonomics more in line with other moto-cross bikes of that time period. This picture courtesy Frantisek Kusovsky.