Harley-Davidson FL is a model designation used for Harley-Davidson motorcycles since 1941, when F referred to the new large capacity 74 cui (1200cc) variant of the V-2 Overhead valve engine (″Knucklehead″) that was introduced in 1936 as Model E with 61 cui (1000cc). The presence of an additional letter L indicated higher compression, offering more power but requiring higher octane gasoline. In 1950s, the low compression version was discontinued, and in 1952 also the low capacity EL, making FL the standard engine and model designation for decades to come.
Until the 1970s, all Harley-Davidson bigtwin FL models came with a front wheel that had the same size as the rear wheel, 5.00-16, and with large fender and wide fork to match, often combined with fairing, bags and additional chrome accessories as ″full dresser″. Customers often slimmed down the factory FL to create a ″bobber″ or even ″chopper″, removing the fender, the sheet metal and big head light, even adding slim 3.00-21 front wheels from other makes, or the whole fork of the smaller Harley-Davidson Sportster XL models that were introduced in 1957.
In 1971, the Harley-Davidson FX ″Super Glide″ was introduced as a ″factory chopper″, combining the FL frame and drive train with the smaller XL front end, basically creating the third, intermediate model range FX that sold and sells well. Since then, the FL prefix indicates that the traditional 16-inch front wheel and big fenders are used on ″Dresser″ Touring series or the traditional styling ″Heritage″ variants of the Softail series, while FX is used on sportier models or the chopper-like Softails with rather thin front wheels.
The FL was introduced to the Harley-Davidson model line in 1941. It used a 74 cu in (1,210 cc) version of the "Knucklehead" OHV engine that powered the EL in 61 cu in (1,000 cc) 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 80 cu in (1,300 cc) flathead engines.[1]
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 self-adjusting hydraulic lifters and aluminum cylinder heads to reduce weight and improve cooling.[2] The U and UL flathead twins were discontinued in 1948, leaving the OHV EL and FL models as Harley-Davidson's large-frame motorcycles.[3]
В 1949 году, через год после получения двигателя Panhead, FL получил новую переднюю подвеску с телескопической вилкой с гидравлическим демпфированием, заменившую рессорную подвеску с ведущим рычагом того времени. [4] [5] Эти вилки были стандартными для всех больших двойных моделей 1949 года, включая E, EL, F и FL. [5] Компания Harley-Davidson предложила на этих моделях пружинную подвеску [4] [5] и рекомендовала их использование на колясках, поскольку стандартные гидравлические вилки не имеют подходящего выноса . [5]