A 2004 Harley-Davidson FLSTF/I Fat Boy has an oil capacity of 3.5 quarts, but other 2004 Harley-Davidson motorcycles have different oil capacities. This particular motorcycle has an air-cooled twin-cam 88B engine.
Another 2004 Harley-Davidson, the FLHTCUI Ultra Classic Electra Glide, has an oil capacity of 4 quarts. This motorcycle has the same engine as the FLSTF/I Fat Boy. Both motorcycles come in a variety of trims and colors, with features such as security systems, electronic fuel injection and Dunlop tires made exclusively for Harley-Davidson. The fuel capacity of both motorcycles is 5 gallons; there is a 1-gallon reserve fuel tank with a warning light that appears when the main tank is empty.