Honda Motorcycle CB500F front turn signal bulbs use P21/5W size while rear turn signal bulbs use P21W size. The replacement chart covers 2013 to 2018 model years 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.
The Honda Motorcycle CB500F uses two distinct bulb types across its turn signal system: the P21/5W at the front and the P21W at the rear, both conforming to ECE standards recognized in Europe and worldwide.
Both bulb types operate on a 12V electrical system, which is standard for motorcycles in this class.
The P21/5W is a dual-filament bulb rated at 21W and 5W, mounted on a BAY15d bayonet base. The dual-filament design allows a single bulb to serve two lighting functions simultaneously.
The P21W is a single-filament bulb rated at 21W, mounted on a BA15s bayonet base. It serves a dedicated signalling function without a secondary filament.
The BAY15d base of the P21/5W and the BA15s base of the P21W are not interchangeable. The BAY15d features offset pins to prevent incorrect installation, while the BA15s uses a single-contact design with symmetrical pins.
The front turn signal specification for the Honda Motorcycle CB500F remains P21/5W across the 2013-2018 model years.
The rear turn signal specification remains P21W across the same 2013-2018 model years.
Because the front and rear positions share the same wattage on their primary filament (21W), substituting a P21W into a front socket would match the wattage but would lack the secondary 5W filament and use an incompatible base type.