Jawa 350-638 turns 40

In the first half of the 1980s, the import of motorcycles into Bulgaria did not exceed 12-13,000 units, in 1984 it fell to 7,000, and in 1986 it literally collapsed to the symbolic level of 3,900. Thus, the motorcycle culture in the country, which had been built over the course of nearly eight decades, found itself in a state of complete decline. That is why modern motorcycles on the Bulgarian market were a rarity during this period, and the new Jawa models, which became very popular in our country in the post-war era, were now only present here on the pages of the specialized press. This is exactly the case with the new Jawa 350-638, which in 1985 replaced the extremely popular 350-634 model. It was distinguished by a much more attractive design and was equipped with a stylish aerodynamic spoiler with a transparent wind shield, with some of the versions being offered in a metallic color.

Jawa 350-638 turns 40

The sliders of the new front telescopic fork are made of light alloy with a matte black surface. The design of the two silencers in combination with the rubber inserts between the ends of the ribs of the two cylinders and the cylinder heads contribute to a significant reduction in noise levels. The rear swingarm has coil springs with variable pitch and progressive characteristics and centrally located telescopic shock absorbers. The spring preload can be adjusted in four positions depending on the load on the motorcycle and the road conditions.

The new, much lighter engine is cast from an aluminum alloy, with pressed cast iron liners in the cylinders to ensure high wear resistance. Compared to the cast iron cylinders of the previous model, the new design improves cooling, which allows for an increase in the compression ratio, and with it the engine's power and economy, especially at higher speeds. The increased compression ratio also contributes to a reduction in the content of toxic components in the exhaust gases. Under the left crankcase cover and the gearbox is a reinforced 5-plate clutch, which can be disengaged not only by the left lever on the handlebars, but also by operating the foot lever for shifting gears.

The engine has a displacement of 344 cc, a compression ratio of 10.2 and develops a maximum power of 19 kW at 5250 rpm. The maximum torque is 33 Nm at 5000 rpm. Lubrication is by crankcase purge, as with any two-stroke engine, with the oil to gasoline ratio being 1:40.

The new horizontal slide carburetor type 2928 SE improves engine performance at lower loads and in transient modes, while reducing exhaust gas toxicity.

There have also been significant changes to the electrical installation, which is now 12 volts. The previous DC generator has been replaced with a much more powerful 3-phase synchronous alternator, equipped with a diode rectifier and vibration regulator.

The overall dimensions of the motorcycle are: length 2080 mm, width (at the handlebars) 710 mm, height 1065 mm. The tank capacity is 17 l, the curb weight (without gasoline) is 156 kg, and the payload is 130 kg.

Car parts AutoPower
Car parts AutoPower

The sliders of the new front telescopic fork are made of light alloy with a matte black surface

The new, much lighter engine is cast from an aluminum alloy, with pressed cast iron liners in the cylinders to ensure high wear resistance