Honda Motorcycle CBX front turn signal bulbs use 1034 size while rear turn signal bulbs use P21W or 1073 size. The replacement chart covers 1979 to 1982 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 CBX uses the 1034 bulb across all front turn signal positions for the 1979-1982 model years.
The 1034 is an ANSI-standard dual-filament bulb rated at 12V and 21/5W, fitted with a BAY15d bayonet base, and is classified as a variant of the 1157.
Its dual-filament design means the 1034 is capable of serving two lighting functions from a single bulb, with the higher wattage filament typically used for the turn signal function and the lower for a secondary function such as running light duty.
The rear turn signal of the Honda Motorcycle CBX uses the P21W for 1979, 1981, and 1982, while the 1980 model year uses the 1073 instead.
The P21W follows the ECE standard used in Europe and worldwide markets, operates at 12V and 21W, and uses a BA15s single-filament bayonet base.
The 1073 is an ANSI-standard single-filament bulb rated at 12V and 13W, also fitted with a BA15s bayonet base, and is described as a lower wattage variant of the 1156.
Although the P21W and the 1073 share the same BA15s bayonet base, their wattage ratings differ significantly, at 21W and 13W respectively, which makes them non-interchangeable despite the physical base compatibility.
The 1034 uses a BAY15d base, which is physically distinct from the BA15s base used by both the P21W and the 1073, making front and rear bulbs non-interchangeable on the CBX.