The Fat Boy began its history as a prototype, created for Daytona Bike Week in 1988. It arrived on the market in 1990, with the 1340 cm3 “Evolution” engine. Such was its success that this model became an integral and obligatory part of the range. For the 2000 model year, the Fat Boy gains in displacement and technology with the Twin Cam 88 ci engine. This block will share the FLSTF epic with 1450 cm3 (10.6 mkg) until 2006, when it climbs to 1584 cm3 (12.5 mkg). In 2012, it takes over the former CVO block, the 103 ci. Its 1690 cm3 engine now delivers 13.4 mkg. Always more displacement and torque, in a style frozen in time.
2018 marks a big break, with a modernized design, a redesigned frame and the adoption of the new Milwaukee Eight twin. The Fat Boy is then available with two possible engine sizes: 1745 cm3 and 14.8 mkg for the 107 ci or 1868 cm3 and 15.8 mkg with the 114 ci. A gain of 1 mkg between the two and a much more present feel. Since 2021, the 107 ci block has been dropped, and only the 1868 cm3 is offered.
Over the course of its career, the Fat Boy has had a number of special series, including 15th / 30th Anniversary, 110th / 115th / 120th Anniversary Harley, Special, S, CVO, and more.
