Honda Motorcycle CBR500R front turn signal bulbs measure P21/5W in size while rear turn signal bulbs measure P21W, with each bulb type serving distinct lighting functions on the motorcycle. The replacement chart covers 2013 through 2018 model years and details bulb size specifications across the vehicle production range.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Honda Motorcycle CBR500R uses two distinct bulb types across its front and rear turn signal positions for the 2013-2018 model years: the P21/5W at the front and the P21W at the rear.
The P21/5W is a dual-filament bulb rated at 12V with a 21W primary filament and a 5W secondary filament, mounted on a BAY15d bayonet base.
The BAY15d base on the P21/5W is an offset-pin bayonet fitting, which physically prevents it from being inserted in place of a single-filament bulb with a different base type.
The P21W is a single-filament bulb rated at 12V, 21W, and uses a BA15s bayonet base, which has a single center pin rather than the dual offset pins of the BAY15d.
Because the front position uses a BAY15d base and the rear uses a BA15s base, the two bulb types fitted to the Honda Motorcycle CBR500R are not interchangeable with each other.
Both the P21/5W and P21W conform to ECE standards, indicating they are rated for use in Europe and other markets that follow ECE lighting regulations.
The dual-filament design of the P21/5W, as fitted to the front turn signal, allows a single bulb to serve more than one lighting function, with the 5W filament typically serving a secondary role such as a position or daytime running light.
The front turn signal specification of P21/5W remains consistent across all six model years listed, from 2013 through 2018, with no variation in bulb type across that period.
The rear turn signal specification of P21W is likewise consistent across the same 2013-2018 span, with no change in bulb type recorded for any of those years.