The 9003 bulb is the sole headlight bulb type specified for the Yamaha FZ750 across all listed model years, covering both the high beam and low beam positions for 1985-1988.
The 9003 is a dual-filament halogen bulb, meaning a single bulb unit contains two separate filaments, one rated at 60 watts for high beam output and one rated at 55 watts for low beam output.
Because both the high beam and low beam headlight positions on the FZ750 use the same 9003 bulb, a single bulb type serves both functions on the motorcycle.
The 9003 bulb operates on a 12-volt electrical system, which is consistent with the standard electrical architecture found on motorcycles of this type.
The 9003 designation follows the ANSI standard, which applies to the United States and Canada, and governs the bulb's electrical and physical specifications.
The 9003 bulb uses a P43t base, which is a bayonet-style mount with a 43mm flange. This base type determines physical fitment into the headlight housing and is not interchangeable with bulbs that use different base configurations.
The 9003 bulb is also commonly cross-referenced with the H4 bulb designation used in international markets. While these two types share similar electrical ratings and a dual-filament halogen design, the P43t base of the 9003 and the P43t base of the H4 are functionally equivalent, though regional certification differences exist between the two designations.