Honda Motorcycle GB500 uses a 9003 bulb size for both high beam and low beam headlight applications. The replacement chart covers 1989 to 1990 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 is a dual-filament halogen bulb operating at 12 volts, with a high beam output of 60 watts and a low beam output of 55 watts. It uses a P43t base, which is a standardized bayonet-style fitting common in automotive and motorcycle lighting applications.
The 9003 designation follows the ANSI standard used in the United States and Canada. This classification system defines precise electrical and physical parameters, ensuring consistent performance across compliant bulbs from different manufacturers.
Because the 9003 carries both filaments within a single bulb, it serves the Honda Motorcycle GB500's high beam and low beam functions simultaneously. Both the 1989-1990 model years use this same bulb for each function, meaning a single bulb type covers all headlight positions on the motorcycle.
The P43t base is not universally interchangeable with other base types. Bulbs sharing similar wattage or voltage ratings but carrying a different base designation are not compatible with sockets designed for the P43t fitting.
The 9003 bulb is sometimes cross-referenced with the H4 designation used in international markets. While the two share functional and electrical similarities, they are defined under different standards, and fitment compatibility depends on the specific socket and retaining hardware present on the vehicle.