In 1973, engineers at the JAWA People's Enterprise developed a new model of motorcycle belonging to the large Java-350 family. It was equipped with a two-stroke engine with a displacement of 350 cm 3 , which has proven itself on previous models. This model was called "Java-634" and was produced with minor improvements for nine years (until 1982).
On the Soviet market, Java-634 was present with the designation 634/01. For the domestic market, the model 634/4/03 was produced. They did not have fundamental differences, with the exception of 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 established European standards in terms of noise level (84 dB).
Description of the Java-350 motorcycle (type 634)
Destination
Motorcycle "Java-634" is a single-track vehicle designed for the transport of one or two people, as well as goods with a total mass of up to 180 kg. It is designed to travel not only on paved roads, but also on country roads, which made it extremely popular in our country. It is possible to attach a side or rear trailer to the motorcycle using additional parts.
Engine
The power unit is a two-stroke engine with an air cooling system with a volume of 350 cm 3 , capable of accelerating a motorcycle to 128 km / h. Two cylinders are located across the longitudinal axis with a forward inclination of 25 ° C. The fuel tank has a volume of 16 liters and a fuel consumption of 4 liters per 100 km. Featuring high reliability and durability, it has excellent throttle response and low noise level. For perfect operation, a mixture of gasoline with oil in a proportion of 1:30 must be poured into the tank.
Transmission
An oil bath motorcycle clutch is multi-disc, with steel discs and a fireproof pad. To control it, the clutch lever is located on the left side of the steering wheel. In addition, a semi-automatic shutdown is provided when the gear ratio is changed .
The gearbox is made four-speed with sliding gears. For gear shifting there is a foot handle combined with the engine start handle.
Chassis
"Java-634" received a new design of the frame, which is made with a rotary boom, which has the necessary strength and rigidity when operating a motorcycle with or without a sidecar.
Motorcycle brakes are independent drum type, with mechanical drive. Braking by the front wheels is carried out using the handle located on the steering wheel on the right side, while the rear wheels use the foot pedal (also on the right).
The front wheel, as well as steel coil springs with hydraulic shock absorbers, are fixed in a telescopic fork, which ensures their good work when driving on rough roads.
The rear pendulum fork, in which the wheel is fixed, provides good stability when driving on wet and slippery roads thanks to a fairly wide support.
Electrical equipment
A 6-volt battery ignition system is used on a Java-634 motorcycle. A six-pole generator with a rated power of 75 W, on whose case brushes, breakers and capacitors are installed, is attached to the engine crankcase. The battery is located under the cushioned double seat.
Four control lamps are located on the instrument panel: red - to control the ignition system (goes off when the generator starts to work), blue - to turn on the high beam, green - turn signal, yellow - neutral position of the gear lever.
Motorcycle "Java-634", the characteristics and appearance of which can not without reason be considered the pride of Czechoslovak designers, was produced in several versions. The latest of them was 634/7, which, with minor design changes, retained all the basic details inherent in the Java-350/634 generation.