Suzuki Motorcycle S40 Boulevard Parking Light Bulb Size

The Suzuki Motorcycle S40 Boulevard uses a P21/5W bulb for the parking light component according to the provided technical specifications. Available information covers the specific time range from 2005 through 2019.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2011-2019	P21/5W
2005-2009	P21/5W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W

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Additional Notes

The Suzuki Motorcycle S40 Boulevard uses the P21/5W bulb size for its parking light across the 2005-2009 and 2011-2019 model years.
The P21/5W is a dual-filament bulb, with one filament rated at 21 watts and a second rated at 5 watts, allowing it to serve two distinct lighting functions within a single housing.
This bulb operates on a 12-volt electrical system, which is standard for motorcycle applications.
The P21/5W uses a BAY15d bayonet base, an offset twin-pin mount that is designed to allow installation in only one orientation, preventing incorrect filament alignment during fitment.
The P21/5W is governed by ECE (Economic Commission for Europe) standards, meaning it is recognized and used across European and international markets rather than being exclusive to North American specifications.
Because the BAY15d base is offset, it is not interchangeable with the BAY15s base, which is a single-filament bayonet fitting with symmetrically placed pins. Substituting one for the other is not possible without a base mismatch.