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Motorcycle Investor mag

Moto Guzzi Le Mans 850

(by Ian Falloon, Feb 2022)

Good looks and performance to match. Meet the 850 Le Mans

The mid-1970s was a halcyon time for the Italian motorcycle industry with all the major manufacturers producing class-leading sporting machines. Determined not to be outdone by Ducati, Laverda, and MV Agusta, in 1975 Moto Guzzi released their spectacular 850 Le Mans.

Although derived from the existing 750 S and 750 S3 the Le Mans was faster and more stylish. With its cast alloy wheels, seat partly covering the fuel tank and small fairing with orange “Day-Glo” front section the Le Mans established a new order emphasising style over function.

For the 850 Le Mans Moto Guzzi’s brilliant engineer Lino Tonti lengthened the stroke of the V7 Sport 750cc engine to 78mm and with 83mm pistons the displacement was 844cc. Most of the performance boost over the 750 S3 came from the cylinder head, with larger valves, higher (10.2:1) compression ratio, and a pair of Dell’Orto 36mm carburettors breathing through velocity stacks.

The high domed pistons increased performance, but cylinder flame propagation was inferior and the Le Mans engine was prone to detonation and running hot. To improve throttle response the Le Mans also had a thinner and lighter flywheel.

Another update was to the exhaust system. Painted matt black to complement the rest of the styling, this featured single-walled 40 mm header pipes, with a balance pipe across the front of the engine. Although quiet and efficient, the main problem with the exhaust system was the black paint wasn’t very durable and rusted prematurely.

The claimed power for the Le Mans was 80 horsepower at 7300 rpm, but this was an optimistic claim.

Like the engine, the 850 Le Mans chassis was also quite similar to the 750 S3. The 35mm cartridge front fork included thinner walled tubes and the light alloy Borrani rims made way for cast alloy FPS wheels, still with the same WM3 rim sizes (2.15x18 inch).

The Le Mans also featured the integrated braking system of the 750 S3 with Brembo 08 calipers, two drilled 300mm front discs and a 242mm rear disc. These brakes were extremely effective, and certainly amongst the best available in 1975. Although the 198kg dry weight was considerable for a sporting motorcycle, and the 1470mm wheelbase moderate, the Le Mans was densely packaged and extremely compact.

But the raison d'être for the Le Mans was really about style more than performance. During the mid-1970s many European manufacturers saw the factory café racer as a way of countering the threat of cheaper, faster and continually improving Japanese motorcycles.

BMW started the trend with their ground-breaking R90S at the end of 1973, Norton followed with the John Player 850 of 1974, and in 1976 Ducati decided to put their limited edition 900 Super Sport into regular production. But none of these were as successful stylistic creations as the Le Mans. The Le Mans may have suffered from marginal execution and indifferent quality, but more than any other motorcycle epitomizes the mid to late 1970s café racer style. And unlike some other deliberately styled motorcycles the Le Mans has stood the test of time.

The Le Mans was the right bike at the right time, offering similar performance to the Ducati 900 SS and Laverda 1000 3C, in a more civilised package. Tonti’s magnificent frame was still more than up to the task of harnessing the power of the 90-degree V-twin and the Le Mans remained one of the best handling motorcycles available. With the excellent integral Brembo braking system it was hard to find a better balanced all round sporting motorcycle and the inclusion of an electric start and shaft final drive made it easy to live with.

The Le Mans was a class-leading machine, and it had the looks to match. One of the great sporting motorcycles of the mid to late 1970s, the Le Mans was a masterpiece.

See the original 1978 road test from Two Wheels magazine.

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