What Might Have Been: The Lambretta GP Racer

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The Lambretta GP racer.
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The 90-degree V-twin has its crankshaft mounted inline with the frame, which pushes the cylinders out into the cooling breeze.
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The 90-degree V-twin has its crankshaft mounted inline with the frame, which pushes the cylinders out into the cooling breeze.
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Vittorio Tessera with the racer today.
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The bike as found.
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The rear drive is by driveshaft, which is unusual for a race bike as a simpler chain drive setup would have saved weight.
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The Lambretta GP racer.
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One of the racers on track.
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The factory with two engines.
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The V-twin on display at the Milan show in 1951.

Here’s a simple question: Name the Italian motorcycle manufacturer that has been synonymous with transverse, overhead-valve V-twins since 1967? Yes, you genius, it is Moto Guzzi.

Now answer this: Name the Italian company that revealed a similar V-twin at the International Milan Fair in 1951. Here’s a hint: It isn’t a motorcycle manufacturer. Still thinking? OK, let’s put you out of your misery.

Lambretta quickly became a giant of post-World War II transportation in Italy with scooters inspired by the rugged U.S. military Cushman runabout. It even built racing versions for Italy’s early national motorcycle championships. But a little-known part of Lambretta’s history was its early ambition to become a major player in Grand Prix motorcycle racing. It is only due to the efforts of a passionate Italian enthusiast that any trace of Lambretta’s GP adventure exists today.

How it all started

Lambretta founder Ferdinando Innocenti’s cheap 2-stroke scooters helped mobilize a nation devastated by war. The financial return from Lambretta’s massive scooter sales in the late 1940s allowed Innocenti to commission Giuseppe Salmaggi to design a sophisticated overhead-camshaft 4-stroke GP racer.

Salmaggi was one of Italy’s leading motorcycle designers of the prewar era and his Gilera Saturno had become the most sought-after privateer race bike of the 1930s. If Salmaggi’s pushrod production-racer Saturno was the benchmark for single-cylinder 500cc Italian racing machinery, his Lambretta V-twin was to boldly go where no GP designer had gone before. 

Sure, there were inline 4-cylinders from Gilera, and soon from MV Agusta, plus a 120-degree V-twin from Moto Guzzi, but when the Lambretta was first displayed at the 1951 Milan show there was nothing like it on earth.

What was all the fuss about?

Lambretta’s GP effort is considered to be the result of a commercial stand-off between it and Moto Guzzi. Lambretta intended to expand into motorcycle production, but Moto Guzzi was opposed to it. Defiantly, Lambretta built and developed its 250cc GP racer over three years, perhaps as a show of its design strength. Lambretta was on a roll in the early 1950s, even running a small supercharged 125cc streamliner to three world records. 

Grand Prix racing motorcycles of the time often looked like a work in progress. Form followed function rather than style leading the way. Not so with the Lambretta racer. It looked more like a production model than a prototype GP racer. A super clean unit-construction engine, unique frame design and carefully contoured bodywork combined in a glorious statement of Italian innovation. 

The result was described as a “masterpiece in engineering” by a major motorcycle newspaper. The 90-degree V-twin engine had its crankshaft mounted inline with the frame, not across it, which pushed the cylinders out into the breeze for better cooling. The square 54mm by 54mm bore and stroke gave a capacity of 247cc and a claimed power output of 29 horsepower at 9,000rpm on pump gas, with a top speed near 106mph.

Much thought had gone into the design. The alloy heads contained two valves each, controlled by triple-coil springs (not the more usual two) and actuated by a camshaft that ran in small ball bearings (not bushings) with pressure-fed oil. The camshaft was driven by a shaft and bevel gears off the crankshaft.

The bullet-shaped front of the crankcase contained a flywheel-mounted magneto with a tachometer drive above it. Behind the engine was a 5-speed transmission with positive-stop action and a heel-toe lever. Strangely, rear drive was by shaft, a much heavier option than using a conventional chain. However, the rest of the little powerhouse was pure racer; generous finning covered much of the engine and the large oil tank, which had an easy-access filler. 

The chassis was as interesting as the engine. A large-diameter spine curved back to steel plates. Tubes ran forward from these plates to hold the engine. There were no front downtubes. The front forks were conventional telescopic, but the rear was a torsion-bar setup with adjustable friction dampers.

Full-width light alloy brake hubs and 2-inch rims with Pirelli tires completed the top-shelf specifications. The Lambretta appeared at the Milan show ready to race, which was no surprise considering that extensive testing had been carried out months before on a local track.

The 250cc racer was redeveloped over the next two seasons, and by the time it was retired in 1953 the engine had evolved into a wet-sump, dual overhead-cam unit with a large oil sump under the crankcase. The original torsion-bar rear suspension had been replaced by shock absorbers equipped with adjustable, air-assisted damping that was very advanced for the day. There were also experiments with twin magnetos.

Sadly, it was a masterpiece that Lambretta poured three years of development into for no return. The race effort never took off, despite enlisting Cirillo “Nello” Pagani, the first Grand Prix 125cc world champion, as test rider. Another leading Italian rider, Romolo Ferri, had just two outings on it, in France and Switzerland, but didn’t get anywhere near the podium in either GP.

A new beginning

Abandoned and forgotten in a corner of the Lambretta factory, no one knew the Grand Prix bike still existed until Vittorio Tessera came along in the late 1980s. A longtime Lambretta enthusiast who had become a guardian of the now bankrupt company’s heritage, he gained the trust and respect of the Innocenti family. Eventually, they gave him the archival remains of the factory, including a strange-looking 4-stroke racer hidden under a dusty blanket.

“The bike was in very dirty condition, but complete and in the same state as when it had last run,” Vittorio says. “I understand there were two of these GP bikes made, but I have never seen them together in a photograph.”

His archive of factory photos contains an image of the race team’s ultra-clean workshop. It shows two complete engines on work stands and shelves of spare parts. One engine appears to be a single overhead-cam version and the other the later dual overhead-cam version.

Vittorio explains how although his racer was the last version, it is a mix and match of components from various years. “It has the dual overhead-cam, wet-sump engine, but it is installed in the first frame built to accommodate the air-assisted twin rear shock absorbers,” he says. “The factory modified the racer step by step from 1951 to 1953.” So maybe there was only ever one running. One day he hopes to get it running again. “I have problems with the camshaft, but I hope in the future to solve this and start the engine again,” he says. That will be a moment worth waiting for, especially running through its original open megaphones. Vittorio’s racer is on display at his spectacular Lambretta museum, Museo Scooter & Lambretta in Rodano, just outside Milan (see Motorcycle Classics, November/December 2013). MC

Photo courtesy the Vittorio Tessera archives.

Not the first

Lambretta wasn’t the first company to design and build a transversely mounted V-twin. That accolade is bestowed on English manufacturer AJS and its short-lived S3 500cc transverse V-twin of 1931. A tourer with sporting pretensions, the S3 and its parent company were soon consumed by the Great Depression and a corporate takeover by fellow British marque Matchless. The model lasted just six months. 

German motorcycle manufacturer Victoria forged its reputation in the 1920s on a range of overhead valve singles and 4-stroke twins. After World War II the Munich factory rebuilt its corporate image on 2-stroke scooters and mopeds. Then in 1953 it launched its first big new 4-stroke, a 348cc transverse, overhead-valve V-twin called the Bergmeister. Its engine was unit construction with a shaft rear drive. 

Japanese manufacturer Marusho built mopeds and motorcycles from the late 1940s until the mid-1960s. Its glamour model was the Lilac, a 246cc overhead-valve, transverse V-twin launched in 1960. Generous European styling, shaft drive, electric starting and full-width wheel hubs showed the company’s determination to lead Japanese innovation. 

Sadly, Marusho’s dream ended soon after when a factory expansion program overstretched finances and the company went bankrupt. The company reappeared as a smaller operation called Lilac in 1964.

Photos by the Motorcycle Classics staff.

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