BMW Motorcycle F650ST uses a 9003 bulb size for both high beam and low beam headlight applications. The replacement chart covers 1997 to 1999 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9003 bulb is an ANSI-standard designation used in the United States and Canada, operating at 12 volts with a dual-filament halogen design rated at 60 watts on the high beam filament and 55 watts on the low beam filament.
The dual-filament construction of the 9003 means a single bulb serves both high and low beam functions, as the BMW Motorcycle F650ST uses the same 9003 specification for both headlight positions across the 1997-1999 model years.
The 9003 bulb uses a P43t base, which is a bayonet-style mount with a 43mm cap. This base type is a defining factor in physical fitment and is not interchangeable with other base configurations even when voltage and wattage ratings may otherwise align.
The 9003 and H4 bulb types share the same dual-filament halogen design, 12-volt rating, and 60W/55W output, with the primary distinction being that 9003 is the ANSI designation and H4 is the ECE designation used in international markets. These two types are generally considered cross-compatible in fitment.