One of the most famous motorcycles of the Soviet period is the Java 638. The technical characteristics were quite appropriate for its time. Unlike older models, there was a telescopic front wheel fork, a wiring system, high-quality electrical equipment and the engine itself. Many technical innovations were tested and applied on this particular motorcycle. Many cars still drive and can be seen on city streets or in towns. These are either stunted motorcycles that are reaching their end of life, or beauties that have been restored and tuned by the caring hands of motorcyclists!
Soviet motorcycle "Java" 350 638
The technical characteristics of this device met the requirements for the working class, and there were also a number of technical innovations. For example, the front wheel fork has improved stem density and a better fit. A similar one was installed on ChZ-472. This design made it possible to reduce vibration when driving. The spring tension on the shock absorber has been increased, which also reduces vibration and increases the gear ratio. Particularly useful when driving with a trailer.
The previous Java model had disadvantages, which included electrical equipment, a constant lack of battery charge, small tool boxes and leaking front fork seals. All this has been eliminated in the Java 638 model motorcycle.
Conversion of hatchback 1111 Oka from gasoline to gas Gas consumption of VAZ 1111 Oka after installing LPG
Only when the spool is raised more than halfway above 14 mm does the air flow at the end of the nozzle become sufficiently intense and fuel flow through the econostat begins. However, Renault, together with partners from Michelin tires with reduced rolling resistance, Continental ultra-light braking system, Faurecia seats, Saint-Gobain glass and Posco magnesium components, have developed about a hundred technical solutions, many of which will soon be implemented in the company's production models.
Specifications
Without changing the ignition system, they used a new battery with transparent walls, which provides the equipment with higher voltage. This made it possible to make some changes, for example, installing side reflectors and a rear lamp with an increased viewing angle, brighter and more powerful indicators were installed on the dashboard. A new type of wiring has increased the safety of the motorcycle. “Java” 638 has come closer to world standards; if earlier the sockets for wires were original, then in this model they are common with other manufacturers. At the same time, the network voltage was doubled.
The Java 350 638 motorcycle, whose technical characteristics are higher than those of its predecessors, has also been improved in the mechanical part. The engine design was lightened by using aluminum to create the cylinders. The cylinder now has four channels instead of two, which increases the compression ratio of the gases in the cylinder, the pressure on the crankshaft and, as a result, the power of the unit itself. The cooling system has also undergone changes, the location of the fins has been changed. The carburetor has been preserved from previous models.
The transmission has also been improved, the clutch basket has been enlarged, which has improved the performance and service life of the engine. The force from the springs was greatly reduced. In the reverse drive sprocket, the number of teeth has been reduced by one, which has changed the gear ratio. Following the improvements, the technical characteristics of the Java 638 motorcycle increased, with a maximum speed of 128 km/h.
Fuel: Owner reviews
| Fuel consumption per 100 kilometers for popular cars The latest versions of the Oka, produced at SeAZ since 2006, received a Chinese three-cylinder small engine with a volume of 1000 cm3, which was also installed on the Daihatsu Charade G10. Body type hatchback Number of doors 3 Number of seats 4 Car length 3200 mm Car width 1420 mm Car height 1400 mm Wheelbase 2180 mm Front track 1210 mm Rear track 1200 mm Ground clearance ground clearance 150 mm Maximum trunk volume 630 l Minimum trunk volume 210 l. |
| JAWA club; improvements - Great Voronezh Forum Of course, you can try to install an additional fine fuel filter designed for cars between the tap and the carburetor, but you need to do this carefully - the filter creates resistance to gasoline flowing into the carburetor by gravity. Idle system and transition 1 - idle jet; 2 — idle emulsion tube; 3 - additional jet; 4 - additional emulsion tube; 5 — spool stop; 6 — carburetor body; 7 — idle speed adjustment screw. |
Repair and maintenance
The 12-volt generator of the 638 engine was considered one of the best of its time, and the engine generally corresponded to its time, reliable and lightweight. Although there are also disadvantages. The carburetor is very complex for such a simple motorcycle as the Java 350 638. The carburetor does not change the technical characteristics much. It has small jets that become clogged with the smallest particles. The main disadvantage is starting the engine. When the temperature drops deep into the minus, starting the engine turns into torture with shamanic dances and a tambourine. Gasoline has to be poured through the spark plug holes. Over time, starting problems appear in warm weather; cleaning and adjusting the carburetor does not bring much benefit. The instructions include advice to clamp the ventilation holes when starting the engine, but this does not bring any tangible benefit.
Naturally, over time this defect only becomes stronger. Some solve this issue by replacing the carburetor with a carburetor of a different system.
There is a problem with the lack of tires for Java on sale; they use tires from Izhevsk motorcycles for the Java 638 motorcycle. The technical characteristics of the tires are appropriate, except for the nipple for the camera, it is larger. You have to widen the hole in the wheel rim. With the development of motorcycle power, brakes improved more slowly and the Java has a problem with the rear brakes. When you suddenly try to stop, the brake cover turns out the reaction lever, the cable breaks, the wheels are blocked, then the movement is skidding and there is every chance of a coup and fall. This happens due to an oversight by the motorcyclist when the rear wheel axle nut is loosely tightened, but the design itself is flawed. There may simply not be enough threads on the axle.
It is also worth mentioning the steering lock, which can be pulled sharply to the left enough to break the clutch. The drive drum teeth wear out very quickly. Perhaps the reason is the quality of the metal.
Model appearance
Outwardly, although it was relatively simple, it still attracted attention . The large headlight, with round turn signals protruding from the sides, and the dashboard wells located on top were combined very harmoniously.
And even though the wheels on the motorcycle were spoked, they sparkled very well in the sun.
The tank of the motorcycle was voluminous, but had a neat shape; in the rear there were quite large pads for the driver’s knees . But the most important thing on the tank was the inscription “Jawa”.
The 638 had a double, flat seat divided in the middle by a strap for the passenger to hold onto. glove compartments under the seat and tank on both sides .
This motorcycle received the nickname “Bench” due to the fact that under the seat there were decorative pads that stretched along the entire seat and ended with a brake light. Because of this, the seat was combined with the rear brake light.
The two-cylinder engine was completely open to view, all its components were clearly visible, although its openness played an important role - the engine was air-cooled.
The advantages of this motorcycle included a very stylish look , which Soviet motorcycles, for example, IZH products, were very far from achieving.
In addition to this, the engine was more high-speed , which made this bike unrivaled. Many also really liked the decision to launch a motorcycle.
Its gear shift foot also served as a kick starter; it was enough to press the foot a little into the gearbox housing and lift it up.
Of all the shortcomings of this motorcycle, only the shortage of spare parts . Like any other motorcycle, it could break down and parts were hard to come by.
In appearance, the ZiD Sova 200 motorcycle differed from the Voskhod in its more modern design, which could help attract Russian buyers.
Motorcycle from Ural, which is distinguished by high power and reliability:
Tuning
Tuning cars and motorcycles is an endless construction kit for amateurs. Many people take on this kind of work, but only a few succeed. Strengthening one or another part leads to distortion in engine operation and accelerated wear of parts. As a conclusion, the best tuning would be for the Java 638 motorcycle to bring the technical characteristics to those stated in the passport. This will already be a lot.
To avoid problems with starting the engine, the carburetor is replaced with a carburetor from 634 Java. Many replacement parts are taken from the old model, but they also bring with them old defects. They install parts from Izhevsk motorcycles, but in this case they have to bore out the mounting points due to the difference in size.
The initial material should be as high as possible in terms of parameters, so it’s worth taking “Java” 638 Lux. The technical characteristics of such a device are higher and it looks more solid. In general, if you are learning how to do tuning, it is better to use such a simple and relatively cheap motorcycle. Mistakes will cost less. Be prepared that replacing the gear chain, clutch cable with a hydraulic clutch release system, or replacing the carburetor will entail other work.
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However, Renault, together with partners from Michelin tires with reduced rolling resistance, Continental ultra-light braking system, Faurecia seats, Saint-Gobain glass and Posco magnesium components, have developed about a hundred technical solutions, many of which will soon be implemented in the company's production models. Body type hatchback Number of doors 3 Number of seats 4 Car length 3200 mm Car width 1420 mm Car height 1400 mm Wheelbase 2180 mm Front track 1210 mm Rear track 1200 mm Ground clearance ground clearance 150 mm Maximum trunk volume 630 l Minimum trunk volume 210 l.
Appearance
The appearance is logical and rational. Quite suitable for short trips around the city and countryside. Unlike older models, the rear light has changed, the telescopic fork of the front wheel stands out more against the general background, individual engine parts have been made more noticeable and placed closer to the exhaust pipe, the muffler has been made longer and more voluminous. Thanks to the larger muffler, engine power has increased. The mounting of the gas tank has been changed, now vibration is practically not transmitted to it.
Motorcycle lovers change the glass, install other mirrors, add or change lights, arches, seat and color, and decorative wheels.
Minuses
They traveled on it on long journeys throughout the Soviet Union, carefully wiped it with a cloth after the trip, and sometimes even passed it on to inheritance with the words Keep it, as I kept it. When the generator is running, the red light goes out, when the turn is turned on, the green light flashes, when the motorcycle is set to neutral speed, the yellow light comes on, and when the high beam is on, the blue light comes on.
FAQ
- Do the parts on the 634 and 638 fit together? For the most part, yes. But parts for a more recent model, that is, 638, are more often found on sale.
- How many horses are there in Java 350? Exactly 26 fast horses. True, no one remembers exactly how the Czechoslovak plant measured power, at the crankshaft or at the rear wheel.
- I have an old anniversary car in my garage, I got it from my grandfather, it hasn’t started for about twenty years, but it looks decent. Does it make sense to invest in restoration for the purpose of selling? Yes, if the bike as a whole is in good condition. Collectible pieces can be quite expensive.
- What is the service life of this engine? There are no exact data, but there are reviews from owners who claim that the engine runs 30,000 km or more without repairs.
- How much does the Java 350 motorcycle weigh? Curb weight with all liquids and other things is about 185 kg, dry weight is about 156 kg.
First steps to success
The first motorcycle from which the history of the famous JAWA plant began was presented at the Prague Motor Show in 1929. It was a JAWA 500cc OHV model with a teardrop tank, based on the German Wanderer model. The Java motorcycle was equipped with a single-cylinder 498.7 cc engine with a power of 18 hp, mounted in a double stamped frame. This motorcycle, which accelerated to 95 km/h, even then acquired the characteristic JAWA coloring - red with yellow accents. Subsequent series of this model were devoid of the shortcomings of their predecessor: in particular, a new muffler, an adjustable parabolic mirror appeared, and the front fork began to be assembled from a pressed sheet. However, it was quite an expensive motorcycle for that time, so there was a need to create a new model.
The next model, developed by the English designer George William Patchett, was the JAWA 175cc Villiers motorcycle. It was presented at the Prague Motor Show in 1932 and began to be positioned on the market as “the best motorcycle for little money.” It was a model with a three-channel two-stroke engine with a volume of 172.6 cc and a power of 5.5 hp, which weighed 70 kg and accelerated to 70-80 km/h. In the first year, three times as many JAWA 175cc Villiers were produced as the 500cc Java, as this model became in great demand due to its lightness, compact size and more affordable price. In subsequent years, the motorcycle acquired a saddle-shaped fuel tank, two long mufflers and other structural elements.
The 30s were marked by the release of other Java models - JAWA 250 Special, JAWA 350 OHV, JAWA 100 Robot and JAWA 250 Duplex. JAWA 250 Special was released in 1935, and at that time this model became one of the main products of the plant. The JAWA 250 Special had a 248 cc two-stroke single cylinder engine. cm with a power of 9 hp, the model weighed 95 kg and reached a maximum speed of 100 km/h. Subsequently, the motorcycle was equipped with an Amal carburetor, a new gas tank and muffler. Another motorcycle, the JAWA 350 OHV, released the same year, was intended for sports competitions. It was a model with a 15 hp engine, it weighed 142 kg and accelerated to 115 km/h. The motorcycle was produced not only in a standard version, but also in an improved version, which had more chrome parts, a larger headlight and foot-operated gear shift.
One of the most popular models of the late 30s was the JAWA 100 Robot motorcycle, designed primarily for young people. The CZ plant also produced similar models, and they were considered the best in the small motorcycle segment. JAWA specialists also decided to strengthen their position and developed the JAWA 100 Robot motorcycle, introduced in 1937. It was a model with a 98.8 cc single cylinder engine. cm with a power of 2.6 hp, which was started using pedals from a standstill or from acceleration. JAWA 100 Robot weighed only 49 kg, reached a maximum speed of 65 km/h, and it really turned out to be very popular among young people and light motorcycle enthusiasts. Before the outbreak of World War II, the plant managed to release another new product: JAWA 250 Duplex with a 246 cc engine and 9 hp. The model had a maximum speed of 100 km/h and weighed 115 kg.
Story
The first Java model, produced under license from Wanderer from 1929, had a four-stroke engine with a cylinder capacity of 500 cm3, was quite complex, expensive and was not in demand. Success for the brand came with the development in 1931 of a light motorcycle with a two-stroke engine with a cylinder capacity of 175 cm3. In 1934, the four-stroke Java with an engine capacity of 350 cm3 was mastered, then a two-stroke with an engine capacity of 250 cm3. In 1937, production of the Java-Robot motorbike began.
After the occupation of Czechoslovakia in 1938, the plant came under the control of the German authorities and began producing military equipment. However, the development of new motorcycle models on it continued. By the end of 1944, the company had prepared for production new models of motorcycles with two-stroke engines of 250 and 350 cm3 and a spark plug rear suspension designed by DKW.
After the liberation of Czechoslovakia, the plant was nationalized and resumed motorcycle production in May 1945. In 1946, the new Java 250 model created a sensation at an exhibition in Paris, winning a gold medal. For its smooth ride, the motorcycle received the nickname “Perak” (springy).
Jawa 250 motorcycle engine sound (single cylinder)
Engine sound of Jawa 350 mod. 354/06 (two-cylinder)
In 1953, production of a new family of Java motorcycles with two-stroke engines of 250 and 350 cm3 and a pendulum rear suspension was launched. The motorcycles were produced jointly with another Czech company, CZ.
In 1970, production began of a new series of Java 250-623 and 350-633 motorcycles, distinguished by their original design. The motorcycles had a backbone frame and an engine with a separate lubrication system. In 1973, the Java 350-634 model with a duplex closed frame and a new engine went into production. The production of motorcycles with an engine capacity of 250 cm3 ceased. After modernization in 1984, the model received the index 638 and continues to be produced with minor changes. The total number of Java motorcycles produced in the 80s exceeded 3 million units.
The Java-India joint venture under the Ezdi brand has produced the Java-250 model since 1960, and the Java-350 model since 1983.
During the Czechoslovak Socialist Republic, up to 99% of production was exported, mainly to socialist countries, and the leading importer was the USSR. After the collapse of the CMEA, the production of Java motorcycles decreased sharply, but the company managed to stay afloat and maintain the production of motorcycles of the original design. The range of models has expanded to include motorcycles with more powerful Rotax and Honda engines.
In November 2021, a presentation of completely new Jawa motorcycles took place in Mumbai (India). As part of the presentation, three new motorcycles equipped with an anti-lock braking system ABS were presented - the classic Jawa, Jawa “Forty-Two” and a custom bike based on Java called “Perak”. If the first two of the listed models became available for pre-order from the day of the presentation, then the custom bike will be sold a little later.
