JAWA The Early Years.

We all want a JAWA. Or do we?

For most of us when girder fork motorcycles are talked of we think of English or American machines, and lets face it that’s all we really see at rallies. European motorcycle manufacturers were aplenty in the first 40 years of the last century however very few made it past the borders into the western world. Okay there is the odd Nimbus around and I have seen a couple of German Triumphs but when approached in conversation most can only think of MZ, Cossack, Ural and Jawa, mostly 1950s to 2000 models. A lot of us have owned eastern world motorcycles, I did, a 1976 350 Jawa twin that only had 7600kms on it. I got it off my flatmate in 1981 for free as he couldn’t sell it, such was the reputation of the Jawa twin. Even now I have an original Voshkod 175 tucked away in a shed somewhere with about 4000 kms on the speedo. A gift from another owner who could not sell it.

For a lot of people when asked about involvement with Jawas have a tendency to reply under a muffled breath. So when I came across a very interesting article outlining the first 25 years of Jawa in a 1955 1st edition of the Czechoslovak Motor Review I though that it was definitely worthy of reproducing for Barnstormer readers. Their design and development is just amazing.

The article was written by Dr Josef Pivrnec in 1954 and is a real eye opener as to the early years of Jawa. I am sure you will enjoy the read.

Jawa – An Interesting History.

Twenty -five years ago, in 1929, the first motorcycle with the name JAWA on its tank left the Green Fox Works in Prague. It was a 500 c.c. OHV single of heavy robust construction.

The beginnings of the production of the JAWA motorcycles were not easy. The works had no previous experience either in design or in motorcycle production. The time was not favourable either. The world economic crisis was making itself felt also on the Czechoslovak market dominated then by foreign makes. A few indigenous motorcycle makes struggled hopelessly for further development.

In 1927-28 the works were in search of a new manufacturing program and the management began to think about motorcycle production. Four alternatives came into consideration as to the design of motorcycles which were to be manufactured. The works own design, the Schliha two stroke engine design, Puch or Wanderer.

Unfortunately, there were no favourable conditions for the works own design. The Schliha design proved to be untried and much too complicated. The engine was a two stroke with differential piston. The piston had a tendency to seize after a few miles and there were no means to remedy this fault.

Negotiations for a licence were therefore opened with the Puch and Wanderer factories. In the end Wanderer manufacturing equipment together with manufactured parts for the assembly of the first motorcycles was purchased and so the first machine which in 1929 left the works was a foreign design and made on foreign manufacturing equipment.

The beginnings of the productions of the JAWA motorcycles were therefore not very spectacular. For us however they are of a special significance.

Twenty-five years ago we started to make motorcycles of foreign designs, on foreign manufacturing equipment and with foreign experiences. Today, after twenty-five years we are making motorcycles with the same name JAWA on their tanks as then, but this name stands today as a guarantee of a quality product, of the works own design ranking among the most progressive in the world. The experiences gained during these twenty-five years had to be paid for. They tell not only of successes, but also of errors, mistakes and failures.

In the history of the works three distinct stages of development can be seen. The first stage from 1929 to the beginning of the Second World War is marked with the struggle to overcome the first failures, to gain experiences both in motorcycle design and manufacture and to get free of the bonds of manufacture under foreign licence. The second stage, the years of the Second World War, is marked with the search of new ways of design based on experiences gained. The third stage beginning with the end of the Second World War is the stage of success when the name of JAWA took the road to foreign markets.

The first JAWA model was made under the Wanderer licence and the first motorcycles left the works in 1929. Costly in production, this expensive motorcycle was utterly unsuitable for the impoverished market and was clearly doomed.

That machine was the JAWA 500 OHV which had a single cylinder engine of 498,7 c.c. capacity, bore 84 mm, stroke 90 mm. Output was 18 HP. The engine was of unit construction with the gearbox. It was set lengthwise in the motorcycle and the rear wheel was driven by shaft. The rear brake was on the drive shaft close to the gearbox. The gear change was hand operated by lever. The rigid frame was pressed sheet metal of double construction. The front fork was of interesting design with trailing link and a leaf spring suspended above the front wheel. The machine weighed 386 lbs (175kg).

Some parts were redesigned in the course of production of this model. These were the first independent designs and the first experiences in motorcycle production.

The JAWA 500 OHV model was in production until 1931. The last machines were completed at the beginning of 1932 when the production of the model was definitely stopped. Even after the modifications defects on the rear wheel drive did not disappear. In three years only 1016 machines of this model were made. The production, however, brought experiences. Experiences in design but mainly experiences of technological character. From the point of view of design the machine was comparatively complicated and in the course of production and redesigning it was found that such a costly and consequently expensive machine can be made only if the manufacturing basis is secured by another product commanding a wide market and thus making the works existence secure.

Already in 1929 the management began to consider the production of cheaper motorcycles of a simpler design. For this reason preparatory design work on a two stroke engine was started. Josef Jozif, now chief designer, designed a prototype in accordance with the management’s idea. It was a three cylinder two stroke radial engine with twin piston cylinders and common crankcase. The engine was designed so as to be built into the front wheel.

Not less interesting and complicated was the chassis of the vehicle. It was designed as a three wheeler with two wheels at the rear contracting together when in movement forming thus practically a single wheel and pulling apart when stopping, giving the vehicle the appearance of a three wheeler. A record run was to be undertaken with the prototype and a new Czechoslovak record established. Besides the vehicle was to serve as a basis of design for both a standard motorcycle and three wheeler at the same time.

The prototype of the engine was built (its photograph was unfortunately not preserved). It was not capable of the record run because even as a design it was a failure. This conclusion seems to us obvious today, but only because the design had to go through its development and had to pay with failures for its present experiences.

The radial engine of this vehicle had a common crankcase and its pistons with connecting rods and crankshaft were so disposed as to give a high output – at least theoretically. There is a rule that there is a long way from theory to practice. This was proved to a full extend in this case. The engine had such a poor admission that without a compressor it was not capable of running. The prototype of this vehicle ended its short life behind the screen. And so the first attempt of an independent design met with utter failure. However, it was not quite fruitless. The step from the JAWA 500 OHV four stroke engine directly to a simple two stroke seemed much too big for the works and therefore they tried to find a way to a more complicated two stroke engine design the problems of which however could not then be mastered.

But the attention remained concentrated on a cheap motorcycle with a two stroke engine. In view of the failure of its own design the works adopted for its new model the British Villiers design. Under licence a new motorcycle model was designed, the JAWA 175 c.c. and in 1932 it appeared on the market. This time only the engine was made under licence. The chassis was of the works own design.

The engine was a classical two stroke with deflector piston with crankshaft arms, inlet port on the cylinder side and a single transfer port. The engine capacity was 172 c.c, bore 52.7 mm, stroke 67 mm, output 5.5 HP at 3750 r.p.m. Compression ration 6.7 to 1, cast iron cylinder, light alloy cylinder head, flywheel magneto ignition, Albion three speed gearbox. The motorcycle frame was pressed sheet metal with rigid rear wheel suspension. The front fork of parallelogram design, pressed of sheet metal. The fuel tank was located under the frame. The construction of the motorcycle makes it clear that the design was aimed at the lowest possible price.

The JAWA 175 c.c. model gained quick popularity among the buying public. It made a break in the prevailing high price level and contributed considerably to popularize motoring. It was a model that met the requirements relatively well of the Czechoslovak market at the time, but with few exceptions did not reach other markets. For a long time it formed the production basis of the works, later together with the JAWA 250 two stroke. It remained in production until 1946.

In the course of its production it underwent a number of modifications. First of all the fuel tank was altered. In 1938 the engine was redesigned and instead of the deflector piston engine a flat top piston engine with inverse scavenging was introduced. From the point of view of design the motorcycle was quite good, cheap to make and to some extent corresponded to the conception of a utility motorcycle. Its production brought a wealth of experiences both in design and manufacture of two stroke engines utilized later in the design work on new models.

At the same time as the JAWA 175, a new JAWA 350 four stroke SV model was being prepared in 1931 and 1932. This model was to replace the formerly produced JAWA 500 OHV.

The prototype of this motorcycle was ready in 1932. It was based on comparatively luxury requirements. The engine was equipped with an electric starter and its conception as a whole proved clearly that this was an expensive de-luxe motorcycle. The prototype was based on experiences gained with the production of the JAWA 500 OHV and presented a number of original elements of design. The rear wheel was shaft driven as on the JAWA 500 OHV. The gearbox was located at the rear wheel.

The results of the prototype tests proved very satisfactory, but the design was from the manufacturing point of view very exacting and costly, so that it never reached the production line. This attempt at an original design again did not prove successful, not because of bad design but due to wrong conception as the machine could not have been made any cheaper than the existing JAWA 500 OHV.

1934 means a considerable increase in the number of models and a certain adjustment of the manufacturing program. Besides the JAWA 175 two stroke, designs of the JAWA 350 OHV and SV, the JAWA 250 OHV and JAWA 250 two stroke were ready. The 350 OHV and 250 OHV were at the time designed as road racing models. The JAWA 350 SV and the JAWA 250 two stroke were put in series production.

The JAWA 350 SV was developed from the prototype made in 1932. Its design left the luxury requirements embodied in the original prototype and the machine was redesigned so that it had a normal kickstarter and final drive by chain. Its frame too had been considerably simplified to make it lighter and simpler to produce. But the original pressed metal sheet conception remained. The engine was built on the works own experience and its design permitted it to be made in two alternatives, either SV or OHV. The SV model was of 346 c.c. capacity, bore 70 mm and stroke 90 mm, 14 HP was at 4200 r.p.m. It had an iron case cylinder, cylinder head of special iron casting, coil type ignition, and a two slide AMAL carburetter.

Originally the British Villiers engine design with flat top piston and cross scavenging was to be utilized for the JAWA 250 two stroke. This design was not put in series production as it appeared in the course of prototype testing that these engines had considerable defects, mainly overheating and high fuel consumption. The cause was the imperfect scavenging of this system. That is why the Schnürle system of inverse scavenging was adopted. This design proved successful and was in time further improved by the works. The chassis of this machine was substantially of the same design as that of the JAWA 175. The frame was pressed metal sheet with rigid rear wheel suspension and pressed front fork of the parallelogram system. The engine had a capacity of 248 c.c., bore 63 mm and stroke 80 mm. Output was 8.5HP at 3750 r.p.m. Compression ration of 6 to 1. The cylinder was of special iron casting, the cylinder head of light alloy. Ignition by flywheel magneto.

At the same time the original 175 c.c. was in production another model was introduced as the JAWA 175 SPECIAL. The engine dimensions remained the same, but the output was increased to 6 HP at 3750 r.p.m. In appearance this machine differed from the normal model by its finish with more chromium plating.

The JAWA 175 and 250 motorcycles were manufactured in great numbers and so formed the production basis of the works. The yearly production figures varied between four and five thousand machines.

In 1935 yet another model was put in production; The JAWA 350 OHV. This model was designed as a sports machine. It was the works own design with no foreign elements. Its design was derived from the 350 SV model with a number of identical details with the exception of the cylinder and cylinder head. The capacity of the engine was 346 c.c., bore 70 mm, stroke 90 mm, overhead valves with push rods, 15 HP at 4000 r.p.m. compression ration 6 to 1. The cylinder was iron cast, the cylinder head of special iron casting, coil type ignition. The machine had still a number of defects. The engine output was good and so was the top speed, but the lubricating system was out of date, the valve gear not being lubricated. It suffered from ignition defects, and the dynamo having the wrong drive ratio. Its riding qualities were not outstanding either. The motorcycle was however relatively popular with sportsmen and if carefully maintained met on the whole the requirements of its circle of customers.

During the two years between 1935 and 1936 it was in production together with the JAWA 350 SV. The design of the time marked by the tendency to abandon SV designs especially in sports machines forced the works to stop the production of the 350 SV in 1936 and to carry on with the JAWA 350 OHV model which was further improved.

After that only three models remained in production: JAWA 175, JAWA 250 and JAWA 350 OHV. The first two were intended as utility machines, the 350 OHV model as a sports motorcycle. The manufacturing program had in this way a more definite line and the works concentrated on improving further these models.

The wide demand created by the production of the JAWA 175 led the works to consider the possibility to make a still cheaper model for 1936, a bicycle with an auxiliary engine which would command an even wider market.

At first it was considered to use a French design, but this idea was abandoned and an independent design was worked out. A new lightweight motorcycle model was prepared for production, the JAWA-ROBOT designed by today’s’ chief designer Jozif. And so after eight years of motorcycle manufacture the works came with another of its own designs, free of foreign influence, created as a result of experience gained. The motorcycle was designed as an autocycle to correspond with the transport regulations then in force which prescribed auxiliary pedals for a vehicle intended to be exempt from its strict clauses. The pedals were introduced for purely formal reasons as the engine had a sufficient enough output to propel the vehicle under any circumstances. The two stroke engine was 98 c.c. capacity and inverse scavening. Bore 47 mm, stroke 57 mm, 2.7 HP at 3700 r.p.m. Compression ration 6 to 1. The cylinder was of special iron casting, the cylinder head of light alloy. Ignition by flywheel magneto. The frame was in principle of the same construction as on the other models i.e. pressed sheet metal.

The JAWA-ROBOT model gained great popularity with the public. The yearly production went up to 5,000 units. It remained in production until 1946 when unfinished series from 1939 and 1940 were assembled.

In 1939 a new model was put in production, a 250 c.c two stroke under the name of DUPLEX-BLOK. As a basis for this design, the existing two stroke 250 was taken, the engine of which had been redesigned. The gearbox was firmly connected with the crankcase so that the power unit formed one block (unit construction). The engine capacity was 246 c.c., bore 68 mm, stroke 68 mm. Output was 9 HP at 3800 r.p.m, compression ratio 6 to 1, cylinder of special iron casting, cylinder head of light alloy, ignition by flywheel magneto of JAWA design. This model possessed the features of the modern two stroke motorcycle of entirely JAWAs own design.

With this model the first development stage in the JAWA motorcycle design came to its end. At the outbreak of the war the following models were manufactured in the works: JAWA-ROBOT 100 c.c, the reconstructed JAWA 175 c.c., JAWA 250 in two alternatives STANDARD and DUPLEX-BLOK and JAWA 350 OHV. All these models bore evidence of JAWAs own design work and the design freed itself in the course of the past ten years of all foreign influence and licence.

In that period of development the works paid attention to everything new that appears in motorcycle design and undertook attempts to improve the existing models.

Various types of suspension have been tried out. Composite torsion bar suspension had been tested. A machine equipped with this kind of suspension took part in an International Six Days’ Trial and finished successfully but the suspension proved unsuitable for serious production. Next, leaf spring suspension of the rear wheel has been tried. A prototype was made and put through road tests which proved this design as utterly faulty, because the wheel had no firm lead and the machine would not handle in corners. Pneumatic suspension of various systems has also been tried, even the use of rubber balls but without positive results.

On the four stroke engines tests with various valve springs have been made, beginning with normal coil springs, hair needle and even leaf springs. The results proved that in the end coil springs are the most suitable for a four stroke engine.

On two stroke engines various types of ports and other designs, such as the two stroke engine with differential piston or a two piston engine with reciprocating pistons and common combustion chamber have been put to trial.

Much attention was paid to the design of compressors. Tests with domestic gas engines have been made too. Extensive tests with engines with a chain driven rotary valve have been carried out. A test two stroke engine with injection of rich mixture into the cylinder scavenged by air has been tried out. The engine had two cylinder, one big working cylinder and a small one for the injection of the rich mixture. This design did not prove successful either. A great number of smaller tests have been carried out.

At the outbreak of the war the works were manufacturing motorcycles on the basis of their own experience and possessed their own mature design. After the end of the war the works had sufficient material to start up motorcycle production quicker than most. All unfinished series and stores of raw materials which the works possessed in 1939 were saved.

First of all the new JAWA 250 was put in production. An early start in production resulted in machines being readied for delivery in 1946. At the beginning of 1946 the works surprised the public of the whole world by exhibiting the new model at the Paris Motor Show. For our motorcycle industry a new stage opened – the march of our motorcycles to all the world markets.
Production of the prepared JAWA 350 OHC was abandoned and a prototype of a second alternative the JAWA 350 twin two stroke was put in production.
In 1951 a new model, the JAWA 500 OHC twin went into production.

The works started with the construction of racing motorcycles in the early years of 1930 to 1932 when racing machines derived from the series JAWA 500 OHV were built.

Immediately after the end of the war the works started on a new design of racing machines. The design developed in the war years could not be utilized as these machines were designed equipped with a compressor (a supercharger, which was banned in international competition after WW2). The new development of road racing machines was taken based on the design derived from the serious JAWA 500. Racers of 500,350 and 250 c.c. capacity were built and are still being developed.

Soon after the beginning of the production of competition motorcycles the works took part in sports contests. The first racing machines built in 1930 took part in the International hill race Zbrasslav-Jìlovìště. Designer G.W. Patchet worked on the racing constructions.

In 1932 the works took part in the greatest international road race, the Tourist Trophy (The I.O.M Tourist Trophy Race), in which the works rider F. Brand was placed fourteenth in a time which entitled him to the Trophy Replica.

In 1933 F. Brand took part in the Grant Prix de I’Europe in Sweden where he finished fifth. The racing machines JAWA achieved their greatest success was in the Tourist Trophy in 1933. Among their riders were G. Wood and T. Span of Great Britain. Wood finished sixth and Span seventh. Two years later 5 machines were sent to take part in the Tourist Trophy but not a single one finished. After this failure the works stopped taking part in the great international road races limiting its participation only to races in Czechoslovakia.

The works had more success with speedway riders competing on their machines in Czechoslovakia, Austria and Germany. The construction of speedway racing machines was later abandoned. Several designs were made shortly after the end of the war. Among them was a speedway racing twin with compressor. The construction proved unsuitable for speedways.

Since the end of the war designer J. Křivka is taking care of the racing machine design. The successes of the JAWA racing machines in 1953 and 1954 show that the way the construction of racing machines has taken is correct. It promises good results in the future.

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