1922 Peugeot Grand Prix Racer
Claimed power: 27hp @ 5,000rpm
Top speed: 100mph (approx.)
Engine: 495cc air-cooled SOHC parallel twin
Weight (dry): 286lbs
Ask your local bike trivia champions when the first double overhead cam eight-valve vertical-twin was produced and by whom. Chances are they won’t even get the country right — and they probably won’t believe you when you tell them the answer: the 500cc 1913 Peugeot Grand Prix, designed by the brilliant Swiss engineer Ernest Henry.
Peugeot history
Peugeot lays valid claim as the world’s oldest surviving motorcycle marque, as the company displayed its first bike — the 1.5hp Motobicyclette — at the Paris Exhibition in 1900. Peugeot originally used supplier engines to power its way into the fledgling motorcycle industry, but in 1906 began using its own large capacity (726cc and 994cc) V-twin engines, essentially derived from their car designs. These proved so powerful and reliable that Peugeot’s reputation swiftly grew outside France, resulting in deals to supply other manufacturers with Peugeot engines.
Two of these were British — while the record books tell us that Rem Fowler rode a Norton to win the first-ever Isle of Man TT in 1907, it was powered by a Peugeot engine. Similarly, a pair of Peugeot-engined, British-built NLGs finished first and second in the inaugural motorcycle race at the new Brooklands track in 1908.
Spurred on by these two-wheeled successes, Peugeot decided to construct its own Grand Prix motorcycle racer, employing the latest in automotive and aviation engine technology, of which its designer Ernest Henry was a proven master. In 1913 he produced the world’s first double overhead cam eight-valve parallel-twin motorcycle, the 500cc Peugeot GP racer that, while unquestionably fast and decades ahead of its time, suffered problems with cylinder head cooling.
Development was interrupted by World War I, and when racing began again in 1919 Peugeot developed a completely new, less complicated design that swept all before it.
Saved and restored
Jean Nougier’s 1922 Peugeot Grand Prix racer shares the same engine dimensions as its pre-WWI double overhead cam sister, measuring 62mm x 82mm for a total capacity of 495cc, and produces 27 horsepower at 5,000rpm. The hefty outside flywheel helped deliver good torque at low revs, and together with the dry sump engine design permitted a strong, narrow crankcase for good crankshaft rigidity, with three main ball bearings. Exposed coil springs and two valves per cylinder — note the parallel exhaust ports — were actuated by a massive vertical shaft running off the right end of the crank. The top bevel housing must have been dealt more than a few mighty blows in the course of a race by the rider’s hand, since the knob of the three-speed gearbox’s hefty hand-shift lever sits about an inch away from it. Remarkably for the time, the Peugeot is a unit-construction engine with gear primary drive and a two-plate dry clutch. Magneto ignition and a single carb with siamesed inlet ports complete the engine specification.
The Peugeot’s rigid frame was almost as advanced for the era as its engine, consisting of a double cradle chassis with twin top tubes and vertical seat pillar, to which the slim oil tank is affixed. The steering head is braced for extra stiffness, and is fitted with Druid-type girder forks with side friction dampers. Apparently, the French bikes handled very well by the standards of the day, confirmed by Jean Nougier after parading the bike in his local Avignon street circuit’s retro celebrations. “The performance can be compared to a good Triumph twin-cylinder roadster from the 1950s,” he told me years ago, “once you get over the handicap of the gear change, which isn’t easy to use. But the acceleration is quite brisk, and the straight exhaust pipes mean it pulls cleanly out of slow corners. And for la periode des annees Vingt (the period of the Twenties), the braking is not too bad,” Nougier said.
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