BMW Motorcycle K100 uses 9003 bulb size for both high beam and low beam headlight applications. The replacement chart covers 1983 to 1986 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 BMW Motorcycle K100 uses the 9003 bulb size across both the high beam and low beam headlight positions for the 1983-1986 model years.
The 9003 is an ANSI-standard halogen bulb recognized in the United States and Canada, operating on a 12-volt system with a dual-filament design rated at 60 watts for high beam and 55 watts for low beam.
Because the K100 uses the same 9003 bulb for both the high beam and low beam positions, a single bulb type serves both functions through its dual-filament construction rather than requiring separate bulbs for each lighting mode.
The 9003 bulb uses a P43t base, which is a bayonet-style mount with a 43mm collar. Any replacement bulb must match this base type to seat correctly in the housing.
The 9003 designation is the ANSI classification used in North America. Its international equivalent is the H4, though fitment compatibility between the two designations depends on the specific housing and base tolerances of the application.