Kawasaki KFX90 Tail Light Bulb Size

The Kawasaki KFX90 tail light utilizes bulb sizes P21W and P21/5W, with specifications varying across the vehicle's production timeline. The replacement chart documents bulb size data spanning 2007 through 2022.

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
2021-2022	P21W
2019	P21/5W
2007-2017	P21/5W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W

Other Locations

Additional Notes

The P21/5W is the predominant tail light bulb type across the Kawasaki KFX90 specification range, appearing in all listed model years from 2007 through 2019, with the exception of 2018.
The P21/5W operates on a dual-filament design rated at 12V with two wattage outputs: 21W for the brighter stop or signal function and 5W for the dimmer running light function, both housed in a single BAY15d bayonet base.
The BAY15d base used by the P21/5W is an offset-pin bayonet fitting, meaning the two locating pins are positioned at different heights around the base to ensure the bulb is inserted in only one orientation, preserving correct filament assignment.
The 2021-2022 model years of the Kawasaki KFX90 use the P21W instead of the P21/5W, representing a shift to a single-filament bulb rated at 12V and 21W with a BA15s bayonet base.
The BA15s base of the P21W differs from the BAY15d base of the P21/5W in both pin configuration and filament count, making the two bulb types physically non-interchangeable despite sharing the same 15mm base body width.
Both the P21W and P21/5W conform to ECE (Economic Commission for Europe) standards, a regulatory framework governing lighting equipment used across European and numerous worldwide markets.
Because the P21W and P21/5W use different bayonet base types, substituting one for the other in a given model year is not supported by the specifications, as the socket design corresponds to the specific base of each bulb type.