A modern incarnation of Praga BD 500…
In 1928, the first Praga BD 500 rolled out of Prague’s Breitfeld-Daněk factory — a very modern motorcycle at the time, featuring what is said to be the first production twin cam motorcycle engine.
It was the brainchild of a young Czechoslovakia aviation designer and passionate motorcyclist, Jaroslav František Koch, who was convinced of the potential of overhead cam engines. In 1923, J.F. Koch had produced his first motorcycle, the JFK, which boasted a 350cc OHC engine with a longitudinal crankshaft.
In 1926, he went to work for the BD (Breitfeld-Daněk) motorcycle works of Prague, where he designed a 500cc “double-knocker” twin-overhead-camshaft, 84 mm x 90 mm, unit-construction single-cylinder engine.
The engine made 15 hp at 4400 rpm, strong enough to push the 170-kg BD 500 up to 65 mph, and made quite the splash in the motoring world:
“The BD 500 not only presented multiple innovative design features, but earned its place in motorcycle history when Koch himself rode the bike from Rome to Prague, covering a distance of 1,480 kilometers in 35 hours and 40 minutes, setting a new endurance record.”
Today, motorcycle collectors and historians still hold the BD 500 engine in high regard:
“Absolutely superb…so good that it had great success in most branches of motor cycle sport, despite being produced in the relatively small numbers associated with such high-end engines.” –Bonhams
Now, in 2023, history is repeating itself with the introduction of the Praga ZS 800 — a modern incarnation of the iconic BD 500. It’s the work of another brilliant Czech engineer, our friend Jan Žuži, whose work we’ve seen in his carbon KX500 and Jiří Heiník’s KTM 1290 Super Enduro R.
Lately, Jan has been working on the Praga Bohema, a 700-hp / 2164-lb / £1.1m Czech hypercar with a carbon fiber monocoque chassis and Nissan GT-R power. However, his two-wheeled roots soon called him back.
“The brainchild of Jan Žuži, an engineer working on the lightweight 700 hp luxury Praga Bohema hypercar, the ZS 800 began life as a passion project to create a BD 500 remake.”
Working with fellow engineer Radek Šebesta and others from the Bohema team, chief designer Jan combined his engineering expertise and passion with Praga’s advanced motor racing production processes, materials, and racing technology to recreate a Czech motorcycling icon for the 21st century:
“The Praga ZS 800 was born, a modern reimagining that retains the character and design of its ancestral BD 500.”
Highlights include a chrome molybdenum steel frame, ultra-lightweight titanium exhaust system, unique forged carbon wheels with carbon tensioned spokes, hydraulic drum brakes, sculpted front fork with fully adjustable Öhlins suspension and titanium spring, Öhlins suspended saddle, and a 773cc air-cooled four-stroke parallel twin engine with bevel gear cam drive and Euro5 compliance, sourced from the Kawasaki W800.
More than 300 hours of five-axis machining is said to go into every build, and the extensive use of advanced lightweight materials means the ZS 800 weighs just 142kg (313 lbs) dry.
What’s more, the bike boats 50:50 weight distribution between the wheels — said to result in a markedly poised ride. Says Jan:
“Strong and extremely lightweight materials — such as carbon, titanium, chrome molybdenum steel, and aviation duralumin — enabled us to reimagine the rigid rear wheel suspension, the front swingarm fork, and the hydraulic drum brakes. These futuristic materials and Praga sports division’s latest production facilities have enabled us to transfer those elegant historical design elements to the present day, and to build a motorcycle with contemporary driving characteristics and a unique feel.”
To us, the BD 500 looks like a remarkable fusion of classic design, motoring heritage, and the most cutting-edge design, production, and materials available today. We’re incredibly proud of Jan Žuži for using his skills and passion to reimagine one of his nation’s motoring icons.
Praga plans to produce just 28 examples of the ZS 800, now available to order with deliveries starting mid-2023. The cost is £75,550 (€86,000) each — Praga says the price is a testament to the intricate engineering that goes into every one of their creations, including the £1.1m Praga Bohema hypercar. To learn more, head over to www.pragaglobal.com/motorbikes/zs800.
Praga ZS 800: Highlights
The ZS is loaded with interesting materials and production features. Here are a few details that caught our eye.
“Titanium is used throughout the design, with almost every screw, axle, nut and bolt of the chassis and engine made from the lightweight, high strength metal. The exhaust system is also fully titanium and weighs just 4.8kg as a result – with select elements constructed using state-of-the-art 3D printing. Premium materials such as duralumin alloys, noble chrome molybdenum steel and forged carbon are also incorporated into the ZS 800’s design.”
“The ZS 800’s unique forged carbon wheels work in harmony with its hydraulic drum brake system – a system chosen to complement both the motorcycle’s style and performance. The hand-woven carbon rims are a complex artistic pattern of overlapping carbon fibre with intricate carbon tensioned spokes to emulate the look of the BD 500.”
“A sculpted front fork sits at the fore of the motorcycle; a structure only made possible through five-axis machining and chrome molybdenum steel. Nestled within the fork is fully adjustable Öhlins suspension with a titanium spring that effortlessly delivers a smooth and exclusive ride.”
Founded in 1907, Praga has produced automobiles, aircraft, buses, trolleys, motorbikes, light tanks, artillery tractors, and even the V3S 5-ton truck that the Czech military used for more than 50 years.
Production ended in 1947, but restarted in 2011 when Praga produced the R4S, a lightweight 400-hp race car that lapped the Slovakia Ring in 1:59, beating Lamborghini’s Gallardo GT3 Supertrofeo LM GTE racer by three seconds.
Today, Praga has continued its racing heritage with machines like the Praga R1, a sportscar with a carbon fiber monocoque chassis that raced in the Britcar Endurance Championship, and the new Praga Bohemia hypercar.