High Quality Content by WIKIPEDIA articles! FL is a model designation used on motorcycles manufactured by Harley-Davidson from 1941 to present. Mostly applied to Harley`s large-framed bikes, including the current Touring series, the FL designation is also used with their Softail series, especially on Softails with traditional styling, 16-inch front wheels, and either Springer forks or large-diameter telescopic front forks.