Honda Motorcycle CBR650F front turn signal bulbs measure P21/5W in size, while rear turn signal bulbs measure P21W in size. The replacement chart covers 2014 through 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 CBR650F uses two distinct bulb types across its turn signal positions: P21/5W at the front and P21W at the rear, a fitment pattern that holds across the 2014-2018 model years covered in the specifications.
The P21/5W is a dual-filament bulb, meaning it carries two separate filaments within a single envelope, rated at 21W and 5W respectively on a 12V circuit.
The P21W is a single-filament bulb rated at 21W on a 12V circuit, serving a dedicated signalling function without a secondary filament.
Both bulb types conform to ECE standards, a regulatory framework recognized across Europe and numerous other markets worldwide.
The P21/5W uses a BAY15d bayonet base, which is an offset twin-pin fitting. The offset pin arrangement is a physical interchangeability safeguard, preventing incorrect installation of single-filament alternatives.
The P21W uses a BA15s bayonet base, a single-pin fitting. Because the BA15s and BAY15d bases are physically incompatible, the front P21/5W and rear P21W bulbs are not interchangeable with each other.
Substituting a P21W into a front turn signal position designed for a P21/5W would be mechanically prevented by the differing base types, reinforcing that the two positions require separate replacement bulbs.
The front turn signal specification of P21/5W on the CBR650F suggests the front housing is wired to utilize both filaments, a common arrangement where the lower-wattage filament serves a secondary function such as a position or daytime running light alongside the main 21W signal filament.