Honda Motorcycle CB250 Nighthawk Turn Signal Bulb Size
Honda Motorcycle CB250 Nighthawk front and rear turn signal bulbs use a P21W size, designated as 1073. The replacement chart covers 2001 to 2008 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 two bulb types specified for the Honda Motorcycle CB250 Nighthawk turn signals are the P21W and the 1073, both of which operate on a 12V system and share a BA15s single-contact bayonet base.
Despite sharing the same BA15s base, the P21W and 1073 are not electrically identical. The P21W draws 21W under the ECE standard, while the 1073 draws 13W under the ANSI standard, meaning a direct substitution between the two would alter the current draw and could affect turn signal flash rates.
The P21W is governed by ECE regulations and is the standard found in European and worldwide markets, whereas the 1073 follows ANSI standards used in the United States and Canada.
Both bulbs are single-filament types, which is consistent with their dedicated turn signal function, as single-filament bulbs serve one lighting purpose rather than combining functions such as braking and signalling.
For the front turn signal, the CB250 Nighthawk used the 1073 bulb in the 2001-2003 model years and transitioned to the P21W for the 2004-2008 model years.
The rear turn signal specification shows a less uniform pattern. The 1073 is listed for 2001 and 2003, while the P21W is listed for 2002 and for the 2004-2008 model years.
Because the front and rear turn signals share the same bulb type within any given model year, a single bulb type is sufficient for all four turn signal positions on the 2004-2008 and 2003 model years. The 2001 model year also follows this pattern. The 2002 model year is an exception, with the front using the 1073 and the rear using the P21W.
The 1073 is described as a lower wattage variant of the 1156 bulb. The 1156 is a widely available ANSI single-filament bulb also with a BA15s base, rated at 12V and 26.88W, making the 1073 a reduced-output version of that same form factor.