Honda Motorcycle NX650 front and rear turn signal bulbs both utilize a P21W bulb size. The replacement chart covers 1988 to 1989 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.
The P21W is the sole bulb type specified for the Honda Motorcycle NX650, appearing in both the front and rear turn signal positions across the 1988-1989 model years.
The P21W operates at 12 volts with a 21-watt output, classifying it as a single-filament bulb intended for signalling functions rather than illumination.
The P21W uses a BA15s bayonet base, which is a single-contact bayonet fitting with a 15mm collar. The "s" designation indicates a single contact pin, distinguishing it from the dual-contact BA15d variant.
The P21W is governed by ECE (United Nations Economic Commission for Europe) standards, a regulatory framework recognized across Europe and numerous other markets worldwide.
Because the front and rear turn signal positions share the same P21W specification on the NX650, the bulbs are interchangeable between those positions within the same vehicle.
The single-filament construction of the P21W means it serves one switching function only, which is consistent with its dedicated turn signal role rather than a combined stop and tail application.