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.
Early FL models
The FL was introduced to the Harley-Davidson model line in 1941. It used a version of the "Knucklehead
engine that powered the EL in form. The FL shared its frame with the EL and with the U and UL, which used a 74 cubic inch flathead
engine. The FL replaced the UH and ULH, which used the same frame with flathead engines.
The FL continued relatively unchanged until 1948, when it and the EL were given redesigned "Panhead
" engines of the same capacities as before. These engines had several improvements over the earlier "Knuckleheads", including aluminum cylinder heads to reduce weight and improve cooling and self-adjusting hydraulic lifters. The U and UL flathead twins were discontinued in 1948, leaving the OHV EL and FL models as Harley-Davidson's large-frame motorcycles.<ref... Read More