The Moto Guzzi V11 Bassa uses a 9003 bulb size for both high beam and low beam headlight applications. The replacement chart covers 1999 to 2000 model 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 bayonet-style fitting with a 43mm collar.
Because the 9003 carries both filaments within a single bulb, it serves the Moto Guzzi V11 Bassa's high beam and low beam functions from one unit rather than two separate bulbs.
The 9003 designation follows the ANSI standard used in the United States and Canada. It is electrically and physically equivalent to the ECE-regulated H4 bulb, though the two designations reflect different regional certification systems.
The Moto Guzzi V11 Bassa used the 9003 bulb across both the 1999-2000 model years for both the high beam and low beam headlight positions.
The P43t base is a keyed fitting, meaning the bulb is designed to seat in only one orientation. This prevents incorrect filament alignment, which would otherwise direct light output away from the intended beam pattern.