The Yamaha XS1100 headlight bulb uses a 9003 size for both high beam and low beam functions. The replacement chart covers vehicle production spanning 1979 to 1981.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Yamaha XS1100 uses the 9003 bulb for both its high beam and low beam headlight positions across the 1979-1981 model years.
The 9003 is a dual-filament halogen bulb, meaning a single bulb unit contains two separate filaments to serve both high and low beam functions within one housing.
Because the same 9003 bulb type is specified for both the high beam and low beam positions, the XS1100 headlight system relies on a single bulb per headlight assembly rather than separate bulbs for each function.
The 9003 operates at 12 volts, with a wattage rating of 60W on the high beam filament and 55W on the low beam filament.
The 9003 uses a P43t base, which is a bayonet-style mount with a 43mm flange. A replacement bulb must carry this same base type to seat correctly in the headlight housing.
The 9003 designation follows the ANSI standard as used in the United States and Canada. The bulb is functionally equivalent to the H4 type used under international IEC standards, though the designations originate from different standardization bodies.
Because the 9003 and H4 share the same physical base and electrical configuration, aftermarket and OEM replacement options for the XS1100 headlight are available under either designation, provided the P43t base and 12V/60W/55W ratings are met.