Honda Motorcycle CB500X front turn signal bulbs use P21/5W size while rear turn signal bulbs use P21W size. The replacement chart covers 2013 through 2018 production 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 CB500X uses two distinct bulb types across its turn signal positions: the P21/5W for the front and the P21W for the rear, both conforming to ECE standards recognized in Europe and worldwide.
Both bulb types share a 12-volt operating voltage and a 21-watt primary filament output, making them part of the same general family of signalling bulbs despite their functional differences.
The P21/5W is a dual-filament bulb, meaning it carries two separate filaments within a single envelope, rated at 21W and 5W respectively. This design allows it to serve more than one lighting function simultaneously.
The P21W is a single-filament bulb rated at 21W, intended solely for single-function signalling applications such as the rear turn signal position on the CB500X.
The front turn signal position on the Honda Motorcycle CB500X requires the P21/5W across the full 2013-2018 model range.
The rear turn signal position requires the P21W across the same 2013-2018 model range.
The P21/5W uses a BAY15d bayonet base, while the P21W uses a BA15s bayonet base. These two base types are physically incompatible with each other, and the bulbs are not interchangeable between the front and rear positions.
The BAY15d base features two offset pins at different heights, a design that prevents incorrect orientation during installation. The BA15s base has a single contact pin and no such offset.