The motorcycle behind the Guareschi brothers’ remarkable achievement was built around the transverse “Big Bore” V-twin derived from the Daytona 1000 IE, developed by the legendary “Dr. John” Wittner. This air-cooled engine featured four valves per cylinder. The production version delivered 122 hp, but it was the chassis package that really made the difference: Öhlins suspension, a box-section aluminum swingarm, and a weight of just 192 kg.

The American adventure was nothing short of sensational. The Guareschi brothers prepared the bike in just a few months, with limited resources and no guarantees of success. The engine was modified without going to extremes, boosting output to around 135 hp. Their decision seemed like an impossible challenge: travel to Daytona and compete in the Battle of the Twins — or rather, win it.

On March 6 and 7, 2006, Gianfranco Guareschi made a clean sweep, claiming two victories in the Battle of the Twins Formula 1 class, ahead of Ducati, Honda, and the ambitious Buell XBRR machines. It was a double triumph nobody had predicted, achieved on a motorcycle that was heavier and less powerful than its rivals. Guareschi also competed in the Sound of Thunder class, open to Superbikes, finishing second.

The following year, history repeated itself. In 2007, Guareschi triumphed at Daytona once again, riding an upgraded MGS-01 sporting a livery that combined the Italian tricolore with the Stars and Stripes. This time, the engine underwent extensive modifications, including the addition of liquid cooling for its two-valve-per-cylinder configuration. The balance of power shifted dramatically, as the Guareschi brothers’ Moto Guzzi, once again ridden by Gianfranco, unleashed an unrivaled level of performance on the legendary Daytona oval.

Once again, decades after Moto Guzzi’s official withdrawal from Grand Prix racing, the Eagle of Mandello soared higher than all its rivals. And that remarkable double triumph remains a unique, unforgettable chapter in the brand’s history.