This is a short synopsis of a tyre shredding Husqvarna, model code S7x36, that was seen at the 2024 Vintage Revival Montlhéry.
Husqvarna was founded in Sweden in 1689 and started out as producers of muskets and weapons, at the request of the King. The company continued to trade for several centuries, and in 1903 took the leap into the world of motorcycles.
At the start, Husqvarna like many other manufacturers used proprietary engines to power their motorcycles, but by 1920 the company was in a position to assemble their motorcycles entirely in house. This independence enabled Husqvarna to push further in their competition efforts, and soon the race team were a force to be reckoned with at Grand Prix and race circuits across the continent.
This is a 1935 factory racer that is housed in the Deutsches Zweirad-und NSU-Museum (demomu.de). It was snapped at the 2024 Vintage Revival in Montlhéry and is quite a special machine with a remarkable provenance.
The machine is one of five works racers that smashed up the circuits in 1935. It dealt some heavy blows to other teams of the time, helped by an impressive power-to-weight ratio. The powerful 499cc V2 overhead-valve motor punched out 41hp at 6700rpm, and through the application of lightweight materials including Elektron (a magnesium extrusion alloy) and Aluminium, the motorcycle was capable of speeds of up to 185 – 190kph.
A feature of the bike that cannot go unnoticed is the discrepancy in the length of the exhausts. Do not be fooled however, as the exhausts are in fact of the same length from exhaust port to tip. It all becomes quite complicated at this point, as many will start to discuss “exhaust reversion” and “positive pressure waves”. To put in simply, exhausts of the same length help to avoid power loss. If you want to know more, there are books dedicated to this phenomenon.
This machine, code S7x36 has had a colourful life in competition. It was initially delivered to Austrian private racer Michael Gayer in 1935 who used it in events such as the Grossglockner High Alpine Road Race. It then went to another speed fanatic – Austrian Hugo Roigk – who raced it for several years on the international scene.
At the end of the 1950s, the machine was raced by Erich Waldmann (father of the GP champion Ralf Waldmann). At this time, the Husqvarna had been modified to keep up with the times, and featured telescopic forks and rear suspension. The worn out machine then ended up in the Deutsches Zweirad-und NSU-Museum, who set about bringing it back to its former halcyon days.
In 1975, the team at the museum set to work to revive S7x36 to the original spec as it left the factory. The task was handed to Karl Reese, and was backed by financial support from donations funded by VFV-members. The restoration was not without its setbacks – one being the rear conrod which had sheared and required a completely new one which had to be made from Titanium instead of the original aluminium-alloy. Once the rebuild had been completed, the bike was raced at classic events; this was however short lived due to a worn-out rear tyre, and lack of optional replacements at the time.
In 2023, S7x36 was finally given the lease of life it deserved, when a rear tyre was finally sourced from Avon. The machine was fettled, and is now used and shown at events around the world.
Thanks to the Deutsches Zweirad-und NSU-Museum for showing the world this wonderful motorcycle.
an article by The Girder Club
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