Kawasaki EX300 Ninja 300 Brake Bulb Size

The Kawasaki EX300 Ninja 300 brake bulb uses a P21/5W size bulb for replacement applications across the motorcycle model line. The replacement chart covers vehicle production spanning 2013 to 2017 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.

Bulb Size by Year Range

Years	Bulb Size
2013-2017	P21/5W

Bulb Specifications

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

Other Locations

Additional Notes

The Kawasaki EX300 Ninja 300 uses the P21/5W bulb type across all documented model years from 2013-2017, indicating a consistent brake light specification throughout the production run covered by these records.
The P21/5W is a dual-filament bulb, meaning a single unit serves two brightness levels within the same housing. The 21W filament activates under braking, while the 5W filament operates as a lower-intensity running or tail light.
The P21/5W operates on a 12V electrical system, which is standard for motorcycle applications of this type.
The bulb uses a BAY15d bayonet base. The BAY15d designation indicates an offset pin configuration, where the two retaining pins are positioned at different heights around the base. This offset is intentional and prevents incorrect filament orientation during installation.
The P21/5W conforms to ECE (Economic Commission for Europe) standards, a regulatory framework recognized across Europe and numerous other markets worldwide.
Because the BAY15d base uses asymmetric pin placement, it is not interchangeable with the BA15d base, which shares a similar appearance but features pins at equal heights. Substituting a BA15d bulb would result in incorrect filament alignment relative to the reflector housing.