Suzuki Motorcycle LT-Z400 QuadSport Z Brake Bulb Size

Additional Notes

• The Suzuki LT-Z400 QuadSport Z uses the P21/5W bulb type for its brake light across the 2003-2014 model years covered in these specifications.
• The P21/5W is a dual-filament bulb, meaning it contains two separate filaments within a single glass envelope. The 21W filament serves the brighter brake or stop function, while the 5W filament handles a lower-intensity running light function.
• This bulb operates on a 12V electrical system, which is standard for small-displacement powersport vehicles.
• The P21/5W uses a BAY15d bayonet base. The BAY15d designation indicates an offset pin configuration, where the two pins are positioned at different heights on the base. This offset prevents the bulb from being inserted in the wrong orientation, ensuring each filament connects to its correct circuit.
• The P21/5W is governed by ECE (Economic Commission for Europe) standards, giving it broad acceptance across European and international markets.
• Because the BAY15d base uses asymmetrically placed pins, a single-filament bulb with a standard BA15d base is not a compatible substitute, as the pin geometry differs between the two base types.
• The consistent P21/5W fitment across all listed model years of the Suzuki LT-Z400 QuadSport Z means a single bulb specification applies to the entire 2003-2014 production span represented in these records.