Harley-Davidson Fat Boy

The Fat Boy's frame is derived from the 1984 "Softail" which appears to have a rigid hardtail chassis but which in fact has a swinging arm with concealed springs that was originally designed in a Missouri garage in the 1970's by "a mechanical engineer" named Bill Davis and later Patented in 1976.[7] Willie G the grandson of Harley-Davidson co-founder William A. Davidson originally turned down engineer Bill Davis' softail concept; but the company later relented, buying the rights and designing its own softail frame in-house.[8]

• After 1994, the exhaust was made seamless.
• In 1996 the master cylinder and switch gear were revised.
• In 1999 a new 1,450 cc (88 cu in) Twin Cam engine for the 2000 model year was used. This necessitated a bespoke engine variant and changes to the frame.
• In 2002 bullet-style indicators, alarm and immobilizer were added.[9]
• In 2005 a 15th Anniversary version was sold, with a "Screamin' Eagle" engine, special paint and custom wheels.[9]
• In 2007 the displacement was increased to 1,584 cc (96.7 cu in)[9] and the transmission changed six speeds.[8]
• The 2010 "Fat Boy Lo" FLSTFB had the lowest ever Harley seat height.[2]
• In 2012 the Fat Boy received the new 1,690 cc (103 cu in) Twin Cam engine along with the rest of the softail range*

The 2018 Fat Boys have a redesigned softail frame with Showa front and rear suspension and new twin-counterbalanced Milwaukee-Eight engines. The two 2018 variants comprise:

• The FLFB 1,746 cc (107 cu in) with 109 lb⋅ft (148 N⋅m), and
• The FLFBS 1,868 cc (114 cu in) with 119 lb⋅ft (161 N⋅m)[10]

The 2018 Softail frame has a modified swingarm with a Showa rear monoshock suspension mounted beneath the seat (replacing earlier twin shocks). So as to provide a more comfortable and better controlled ride with improved handling, the front forks contain a Showa "Dual Bending Valve" (SDBV),[11] a cartridge simulator using two valves to control compression and rebound damping, giving linear damping characteristics proportional to fork stroke speed. Harley-Davidson claims the 2018 chassis is stiffer and lighter than earlier Softail and Dyna platforms.[12] Further upgrades include an LED headlight and 18-inch “Lakester” rims, with wider 160mm front and 240mm rear rubber.[13][14]

For 2020, the Fat Boy is only available with the Milwaukee-Eight 114 engine. Harley-Davidson also produced a 30th Anniversary edition for 2020. [15]

It is one of Harley-Davidson's best selling models, and has appeared prominently in a number of TV shows and movies.[3] The Fat Boy earned a place in American pop culture after appearances in the movie Terminator 2: Judgment Day. One of the motorcycles used in Terminator 2 is displayed at the Harley-Davidson Museum. It appeared again in Terminator Genisys.[2][16][17][18]