The Yamaha EC540 uses a 9003 bulb size for both high beam and low beam headlight applications. The replacement chart covers vehicle production spanning 1979 to 1980.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9003 is the sole bulb type listed across all headlight positions for the Yamaha EC540, covering both the 1979-1980 model years.
The 9003 is a dual-filament halogen bulb, meaning a single unit contains separate filaments for both high and low beam operation.
The 9003 operates on a 12-volt electrical system and draws 60 watts on the high beam filament and 55 watts on the low beam filament.
The 9003 uses a P43t base, which is a bayonet-style mount with a 43mm collar, and fitment depends on this base type matching the socket in the housing.
The 9003 is designated as an ANSI standard bulb, meaning its specifications are governed by the American National Standards Institute and the bulb is rated for use in the United States and Canada.
Because the EC540 uses the same 9003 bulb for both the high beam headlight and the low beam headlight across both listed model years, the two positions share a common replacement part.
The 9003 bulb type is sometimes cross-referenced with the H4 designation used in international markets, though the two are not always interchangeable due to differences in base construction and beam pattern certification.