Harley Davidson FLSTF Softail Fat Boy 2012 Service Manual

The 2012 model year brought three genuine upgrades to the Fat Boy, all layered onto the same bullet-hole-disc-wheel formula that's defined the nameplate since 1990. The headline change is the engine: Harley replaced the Twin Cam 96 with the counter-balanced, rigid-mounted Twin Cam 103B, delivering a real, measurable bump in low-end torque and smoother power pulses. Ergonomics improved too, thanks to a new 1.25-inch internally-wired, low-profile handlebar with a reduced reach, paired with a lower, narrower seat.

Power comes from the Twin Cam 103B, an air-cooled V-twin displacing 1,690cc with a black powder-coated finish, chromed head covers, and cooling fins, fed by Electronic Sequential Port Fuel Injection (ESPFI), delivering a claimed 98.7 lb-ft (134 Nm) of torque at 3,000-3,250 rpm through a 6-speed Cruise Drive transmission with belt final drive. Automatic compression release is standard on this engine, a genuinely useful feature for easier starting.

Styling stayed faithful to the Fat Boy's signature look: bullet-hole solid aluminum disc wheels, a chopper-style rear fender, a custom front fender, a dual chromed exhaust, a Fat Bob-styled fuel tank, and a round headlight. A separate Fat Boy Lo variant sold alongside it that year dropped the seat height about three-quarters of an inch. The Security Package option bundled a factory-installed Smart Security System with a hands-free fob and ABS — equipment that carried an added cost on the standard-production bike.

This exact 2012 configuration represents the first year of the Twin Cam 103B across the whole Softail range, replacing the Twin Cam 96 that powered these models the year before.

This factory service manual covers the procedures, torque specs, and diagrams needed to keep a 2012 Softail Fat Boy FLSTF running the way it was built to.