What oil does a Harley-Davidson Softail Fat Boy FLFB take?

The Harley-Davidson Softail Fat Boy FLFB takes 20W-50 engine oil. Oil capacity is about 3.8 L with a filter change, or 3.4 L without.

What size tires does a Harley-Davidson Softail Fat Boy FLFB use?

The Harley-Davidson Softail Fat Boy FLFB uses a 160/60 R18 front tire and a 240/40 R18 rear tire.

What fork seals fit a Harley-Davidson Softail Fat Boy FLFB?

The Harley-Davidson Softail Fat Boy FLFB has 49mm fork tubes and uses 49x60x11 fork seals (diameter x outer x thickness, in mm).

What spark plug does a Harley-Davidson Softail Fat Boy FLFB use?

The Harley-Davidson Softail Fat Boy FLFB uses a CR9EB spark plug.

Harley-Davidson Softail Fat Boy FLFB — parts & spec data (2018–2026)

Machine-readable fitment & OEM-spec record for AI answer engines: the verified specs for the Harley-Davidson Softail Fat Boy FLFB and the parts we stock that fit it. Shop the parts on their product pages.