The L-twin is a naturally aspirated two-cylinder petrol engine by Ducati. It uses a 90-degree layout and 270-degree firing order and is mounted with one cylinder nearly horizontal.
The next new Ducati engine to appear after the Ducati Apollo was the 90° V-twin, initial Grand Prix racing versions being 500 cc, and the production bikes were 750 cc. There was also the Ducati 750 Imola Desmo that won at Imola in 1972. These engines had bevel gear shaft drive to the overhead camshaft, and were produced in round, square, and Mille crankcases. In the 1980s, these gave way to the belt drive camshaft engines that have continued to this day, in air-cooled and liquid-cooled form. The Mille used a plain bearing crank, like the belt models.
