The Harley-Davidson Fat Boy, is a V-twin softail cruiser motorcycle with solid-cast disc wheels. Designed by Willie G. Davidson and Louie Netz, Harley-Davidson built a prototype Fat Boy in Milwaukee for the Daytona Bike Week rally at Daytona Beach in 1988 and 1989.Fat Boys produced from 1990-2017 are coded FLSTF, and FLFB (& FLFBS) from 2018.