Honda Motorcycle CX500C Custom Turn Signal Bulb Size
The Honda Motorcycle CX500C Custom front turn signal uses a 1034 bulb size while the rear turn signal requires a P21W or 1073 bulb size. The replacement chart covers 1981 to 1982 production 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 Honda Motorcycle CX500C Custom uses three distinct bulb types across its front and rear turn signals for the 1981-1982 model years: the 1034, the P21W, and the 1073.
The 1034 bulb follows the ANSI standard used in the US and Canada. It is a dual-filament bulb operating at 12V with a 21/5W output and uses a BAY15d bayonet base.
The BAY15d base on the 1034 is an offset-pin bayonet fitting, which physically prevents it from being substituted with single-filament bulbs that share a visually similar base style.
The 1034 is a variant of the 1157 bulb. The dual-filament design means it carries separate circuits for two brightness levels within a single housing.
The front turn signal position on the CX500C Custom uses the 1034 for both 1981 and 1982, making it the only position with a consistent fitment across both model years covered in the specifications.
The rear turn signal position differs between model years. The 1981 CX500C Custom uses the 1073, while the 1982 model uses the P21W.
Both the 1073 and the P21W share the BA15s single-pin bayonet base, meaning the two bulbs are physically interchangeable at the socket level. However, their wattage ratings differ: the 1073 operates at 13W, while the P21W operates at 21W.
The P21W follows the ECE standard, which governs lighting regulations across Europe and many other markets worldwide, as opposed to the ANSI standard that governs the 1073 and 1034.
The 1073 is a lower wattage variant of the 1156 bulb. At 12V and 13W, it draws less power than the P21W, which is rated at 12V and 21W despite sharing the same base type.
Because the 1034 uses a BAY15d base while the 1073 and P21W use a BA15s base, the front and rear turn signal sockets on the CX500C Custom are not interchangeable with one another.