The Yamaha FZR400 uses HS1 bulb size for both high beam and low beam headlight applications. The replacement chart covers 1988 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 HS1 bulb is the sole bulb type specified across all lighting positions in the Yamaha FZR400 headlight system for the 1988-1990 model years.
The HS1 is a dual-filament halogen bulb, meaning a single unit contains both the high beam and low beam filaments within one glass envelope.
Because the HS1 serves both the high beam and low beam positions in the FZR400, both circuits draw from the same physical bulb installed in the headlight housing.
The HS1 operates on a 12-volt electrical system and carries a 35W/35W power rating, with each wattage figure corresponding to one of the two filaments.
The PX43t base is the mounting interface of the HS1 bulb. This base type is specific to the HS1 standard and is not interchangeable with common automotive base types such as H4, despite the H4 sharing a similar dual-filament halogen design.
The HS1 is governed by ECE (Economic Commission for Europe) regulations, a lighting standard widely adopted across European and international markets, which defines the bulb's output, beam pattern compliance, and construction requirements.
The H4 bulb, which is physically similar to the HS1 and also uses a dual-filament halogen design, carries a higher wattage rating of 60W/55W and a P43t base. The P43t and PX43t bases are not the same, and substituting an H4 for an HS1 in the FZR400 is not supported by the specifications.