In 1972 Moto Guzzi developed a motorcycle prototype equipped with the decomposable frame of the V7 Sport and the same engine with some modifications. The displacement was increased to 843.6 cm³ (83×78 mm) and two 40 mm Dell’Orto PHM carburettors with recovery pump and intake horn were used. The prototype thus conceived had 82 HP available at 7,500 rpm. The braking system developed by Brembo with connected brakes was also tested on the same bike: the pedal operated the rear disc and the front left disc while the lever on the handlebar independently operated the front right disc.
The Le Mans 850, often improperly called Le Mans 1 or Le Mans Mark I to distinguish it from the following series, was the series motorcycle derived from the 1972 prototype. For the standard version a dedicated chassis designed by Lino Tonti was developed but the power delivered had been reduced to 71 HP, which allowed the bike to reach a top speed of 210 km / h. Presented at the Milan Motor Show in November 1975, it was launched on the market in 1976. Compared to its sister California T3, the Le Mans had a higher compression ratio, larger valves, and 36mm instead of 30mm Dell’Orto carburettors, shock absorber steering and alloy wheels.
The bike had two production series with slight modifications that were made progressively. The first series, of about 2,000 specimens, lasted until September 1976 and is mainly distinguished by the round tail light model 9350 produced by CEV and a saddle named 1 and a half seats which had the characteristic of breaking almost immediately and which was replaced under warranty with a two-seater saddle. The 2 series had the rear light model 211 always produced by CEV and introduced in the De Tomaso period to find synergies also with the Benelli models, a rear fender modified to accommodate the new rectangular light, and left the factory with the saddle two posts which consisted of a single piece of molded foam. Most of the Le Mans 850s were red and black, but some were metallic blue and few were white.