1999 Harley-Davidson FLSTF Fat Boy Technical Analysis & Specification Breakdown
Engineered by Harley-Davidson for the custom - cruiser motorcycle segment, the 1999 Harley-Davidson FLSTF Fat Boy utilizes a 1338 cc (81.6 cu in) air-cooled v2, four-stroke layout. In factory specification, peak output is rated at 56 HP (40.9 kW) at 5,000 rpm while maximum torque reaches 97 Nm (71.5 lb-ft) at 2,350 rpm, transferring power to the rear wheel through a 5-speed gearbox and belt final drive. With a specific output of 41.9 HP per liter and a 2,650 rpm working window between peak torque (2,350 rpm) and peak power (5,000 rpm), the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.
On the scales, the FLSTF Fat Boy measures 305 kg (672 lbs) wet (curb), translating to a power-to-weight ratio of 0.18 HP/kg (5.45 kg per horsepower). Rider ergonomics and chassis geometry center around a 680 mm (26.8 in) seat height — giving shorter riders and urban commuters confident flat-foot reach at traffic stops, combined with a 1,632 mm (64.3 in) wheelbase engineered for planted straight-line stability. The 15.9-liter (4.2 US gal) fuel tank paired with a rated consumption of 5.8 L/100 km provides an estimated theoretical range of roughly 274 km (170 miles) between fill-ups, while factory top speed is listed at 152 km/h (94 mph).
Within MotoLibrary's Harley-Davidson archive, this model family spans 7 indexed model years from 1999 to 2011, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
41.9 HP/L
Power-to-Weight
0.18 HP/kg (5.45 kg/HP)
Power Band Window
2,350–5,000 rpm
Theoretical Range
~274 km (170 mi)
Engine
Displacement1338.0 ccm (81.64 cubic inches)
Engine TypeV2, four-stroke
Engine DetailsV2, four-stroke
Power56.0 HP (40.9 kW)) @ 5000 RPM
Torque97.0 Nm (9.9 kgf-m or 71.5 ft.lbs) @ 2350 RPM
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Torque
Torque is useful for judging real-world pull, especially for touring, commuting and loaded riding.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
