"Java-634" - a popular motorcycle of the seventies

In 1973 engineers of the national enterprise JAWA developed a new model of a motorcycle belonging to the large family "Java-350". It was equipped with a two-stroke engine with a working volume of 350 cm ³ , well-proven in previous models. This model was called "Java-634" and was released with minor improvements for nine years (until 1982).

In the Soviet market, "Java-634" was present with the designation 634/01. For the domestic market, the model 634/4/03 was produced. They had no fundamental differences, except for the engine. "Java", produced for the Czechoslovak market, was equipped with less powerful power units (19 hp vs. 22 hp), so as not to exceed the European noise standards (84 dB).

Description of the motorcycle "Java-350" (type 634)

Purpose

Motorcycle "Java-634" is designed to carry one or two people, as well as cargo with a total weight of up to 180 kg single-track vehicle. It is intended for movement not only on hard-surface roads, but also on country roads, which made it unusually popular in our country. It is possible to attach a side or rear trailer to the motorcycle with additional parts.

Engine

The power unit is a two-stroke engine with an air cooling system of 350 cm ³ , capable of accelerating the motorcycle to 128 km / h. Two cylinders are located across the longitudinal axis with a forward tilt of 25 ^° C. The volume of the fuel tank is 16 liters, fuel consumption is 4 liters per 100 km. Distinguished by its high reliability and durability, it has an excellent acceleration and low noise level. For perfect operation in the tank, it is necessary to pour a mixture of gasoline and oil in the proportion of 1:30.

Transmission

The clutch of a motorcycle, working in an oil bath, is multi-disc, with steel discs and a fire-resistant lining. To control it, the clutch lever is located on the left side of the rudder. In addition, semi-automatic shutdown is provided when changing the gear ratio.

The transmission is made of a four-stage with sliding gears. To change gears, there is a foot handle, combined with the engine start handle.

Chassis

"Java-634" received a new frame design, which is made with a swivel boom, which has the necessary strength and rigidity when operating a motorcycle with or without a sidecar.

The brakes of the motorcycle are independent of the drum type, with a mechanical drive. Braking by the front wheels is carried out with the help of the handle located on the handlebar on the right side, the rear ones by the foot pedal (also on the right).

The front wheel, as well as steel spiral springs with hydraulic shock absorbers are fixed in a telescopic fork, which ensures their good work when driving on a rough road.

The rear pendular fork, in which the wheel is fixed, provides good stability when driving on a wet and slippery road due to a fairly wide support.

Electrical equipment

The Yava-634 motorcycle uses a 6-volt battery ignition system. A six-pole generator with a rated power of 75 watts, with brushes, interrupters and capacitors installed on it, is attached to the engine crankcase. The battery is located under the two-seat cushion seat saddle.

On the instrument panel are four control lamps: red - to control the ignition system (goes out when the generator starts to work), blue - the driving beam, green - turn signal, yellow - neutral position of the gearshift lever.

Motorcycle "Java-634", the characteristics and appearance of which can be reasonably considered the subject of pride of Czech designers, was produced in several modifications. The most recent was 634/7, which, with minor design changes, retained all the basic details inherent in the generation "Java-350/634".