BMW Motorcycle K1 headlight bulbs utilize a 9003 size for both high and low beam functions. The replacement chart covers 1988 to 1993 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The BMW Motorcycle K1 uses the 9003 bulb for both high beam and low beam headlight positions across all model years from 1988-1993.
The 9003 is an ANSI-standard bulb recognized in the United States and Canada, operating on a 12-volt system with a dual-filament halogen design rated at 60 watts for high beam and 55 watts for low beam.
Because both beam positions share the same 9003 specification, a single bulb type serves the entire headlight assembly on the K1.
The 9003 uses a P43t base, which is a bayonet-style mount with a 43mm collar, and this base type determines physical fitment into the headlight housing.
The 9003 and H4 bulb types share the same P43t base and dual-filament halogen construction, though the 9003 designation reflects the ANSI standard while H4 reflects the ECE standard used in many other markets; the two are often considered interchangeable in practice.