The fastest racing CZ models: 350/860 and 420/860

Today, the MotoGP series features Italian brands Ducati and Aprilia, as well as Japanese Honda and Yamaha. Half a century ago, the picture was a little different. On the world's racing tracks, spectators could see the irreconcilable struggle of two rivals-compatriots, well-known in our country - Jawa and CZ.


It is difficult to judge now how events would have developed if the tragedy with Bill Ivy had not happened. But it entailed a strong-willed decision on the part of the communist leadership of Czechoslovakia. Closer to the mid-70s, both local teams stopped participating in the world championships in road racing.


But Czechoslovakian designers at the turn of the last and current decades managed to design extremely competitive machines. First of all, we are talking about the Jawa type 637 with a two-stroke four-cylinder liquid-cooled engine with a working volume of 350 cc. But competitors did not lag behind, moreover, in sports the CZ brand looked much more attractive and successful.

Great cars from a great designer

Of course, the excellent results in the competitions would not have been possible without such ace drivers as Bohumil Staša. Already at the 1971 Brno Grand Prix, he finished second, showing the best result among Czechoslovakian sportsmen at this prestigious competition.

But the greatest credit for these successes still goes to the talented designer František Pudil. He turned out to be the best student of the creator of unusual designs Jaroslav Walter. Since 1966, Pudil worked on several versions of racing motorcycle with different engine sizes.



The first drawings of the future project appeared in the same 1966. And the next year, the production of bike parts based on them began. The concept of the motorcycle drive turned out to be extremely advanced for its time. Many experts agreed that it was several years ahead of the developments of Italian and Japanese competitors. Here is what it contained:

✅ low center of gravity
✅ drive clamping angle – 90 degrees
✅ small frontal area (which improved the aerodynamics of the motorcycle)

Another know-how was the placement of the clutch on the secondary gear behind the gearbox. This solution was later even noted with awards at prestigious competitions. It seemed that new achievements were ahead, but the time until the fateful January 16, 1973 was ticking mercilessly.


The road racing motorcycle type CZ 860 was launched with 350/420 cc engines. The larger version was intended for performances in the 500 cc class. It was the first 4-cylinder model in the history of the brand, the previous ones were 1-cylinder four-stroke. But the old designs ceased to be competitive at the international level in the second half of the 60s.

To bring CZ back to the elite of world road bikes, František Pudil created something completely new, which had very little in common with the previous machines. This primarily concerned the power unit:

✅ twin 4-cylinder XNUMX-stroke
✅ air cooling
✅ DOHC valve mechanism

This arrangement made it possible to create a compact power unit, where sufficient cooling of all elements was guaranteed. However, the width of the engine arranged in this way was the same as that of a two-cylinder engine, which gave the advantage of lower aerodynamic resistance.

Gradual development of the project

The new racing unit was created by 1969. First in a 350 cc version, later with an engine increased to 420 cc so that the motorcycle could also participate in 500 class races. After successive modifications and improvements, the sports bike became a world-class machine.

By the start of the 1972 competition, the creators had managed to prepare only three racing machines. They were two 350-cc motorcycles and one with a 420 cc engine. Here are some of their differences (in brackets are the figures for the more powerful sports bike):

✅ power – 60,5 (72,5) hp at 14 (000) rpm
✅ piston stroke – 54 mm
✅ maximum speed - 245 (260) km / h
✅ fuel consumption – 11 l/100 km

Both models had hydraulic brakes and were virtually identical in technical terms. The larger machine competed in the 500 class. Of course, Pudil made every effort to maximize the cylinder diameter and engine block bearings. Despite his efforts, he was unable to achieve a full 500 cc volume.

The chassis modifications allowed the motorcycle's weight to be reduced. Therefore, during the traditional May competitions of 1972 on the Salzburgring track, Bogumil Staša managed to rise to second place. He confidently continued to hold it until four laps before the finish, when the piston seized up.

The motorcycle also suffered setbacks in the next two races, and the CZ factory ultimately withdrew from the world championship series. Especially since the epochal decision taken in January 1973 obliged the company to curtail its road racing program.


The result was an order from above, which ordered the Czechoslovakian factory teams to no longer compete with each other. The company from Strakonice had to stop developing road bikes and hand over all technical documentation to their competitors from Prague's Jawa. The finished racing equipment was also to be sent there.

Although the first provisions had to be compelled to comply, the last point remained unfulfilled. Thus, the company management and the entire CZ team showed their clear disagreement with their exclusion from the competition.

Three racing machines of the 860 type remained in the ownership of the company from Strakonice. The priceless bikes were stored for a long time in simple wooden boxes in one of the sheds on the company's premises. Later, one of them was sold to a private foreign connoisseur of retro motorcycles. And the other one became an exhibit in the collection of the National Technical Museum of the Czech Republic in 2007.


It would seem that this is where we can draw a minor line in our story. However, it has its major continuation. As you remember, the motorcycle designer dreamed of creating a full-fledged 500-cc bike. Unfortunately, neither the life nor the political situation allowed him to realize his desires.

Enthusiasts bring an original idea to life

But there were three modern connoisseurs who decided to continue the work of František Pudil. Ilya Zachoval, Mirek Tuma and Vratislav Hromádko knew about the dream of the designer, who is no longer alive, and tried to complete the half-century-old project themselves.

Having started to implement the plan back in the days of the great František, they received all the necessary documentation from Strakonice. But after Pudil's death, there was no longer an opportunity to consult with the designer, so the enthusiasts began to choose materials and solutions that were not available in the 70s of the last century. Which, however, did not affect the appearance of the motorcycle and its functionality.


The result was quite decent, so Gromadko began to ride his brainchild, taking part in various competitions and rallies. The resulting sportbike CZ 500/860 makes an incredible roar, which was recently appreciated in England.

It develops a maximum speed of more than 250 km/h, with a power of 103 hp and a weight of 140 kg. According to the creators of the replica, it was not assembled for sale or exhibition in some museum. This is a machine for the soul, reminiscent of the former sports glory of the now defunct model. The implementation of the project cost about 7 million crowns (a little more than 29 million rubles).