Kawasaki VN900 Vulcan 900 Brake Bulb Size

The Kawasaki VN900 Vulcan 900 uses a P21/5W bulb size for brake applications. The replacement chart covers 2006 through 2022 model years with corresponding bulb specifications.

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
2006-2022	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 Kawasaki VN900 Vulcan 900 uses the P21/5W bulb for the brake light position across all specified model years from 2006-2022.
The P21/5W is a dual-filament bulb, meaning it contains two separate filaments within a single glass envelope. The higher-output filament operates at 21 watts for the brake or turn signal function, while the lower-output filament operates at 5 watts for a constant tail or parking light function.
The P21/5W uses a BAY15d bayonet base. The BAY15d designation indicates an offset pin configuration, where the two retaining pins are positioned at different heights on the base. This asymmetric design prevents the bulb from being inserted in the wrong orientation, which would reverse the two filaments.
The bulb operates on a 12-volt electrical system, consistent with standard motorcycle electrical architecture.
The P21/5W is rated under ECE (Economic Commission for Europe) standards, a regulatory framework used across Europe and numerous other markets worldwide.
Because the BAY15d base uses offset pins, it is not interchangeable with the BAY15s base, which is a single-filament bayonet fitting with pins at equal heights. Substituting a BAY15s bulb in a BAY15d socket is not possible without modification.