Honda Motorcycle CB1100 front and rear turn signal bulbs utilize a P21W size specification across both positions. The replacement chart covers 2013 to 2014 production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W is the bulb type specified for both the front and rear turn signals on the Honda Motorcycle CB1100 across the 2013-2014 model years.
The P21W is a single-filament bulb, meaning it serves one lighting function only, which in this application is turn signaling.
The P21W operates at 12 volts and 21 watts, a wattage rating common in automotive turn signal applications where sufficient brightness is required for signaling visibility.
The P21W uses a BA15s bayonet base, a single-contact bayonet fitting where the "s" denotes a single contact pin offset, distinguishing it from dual-contact variants that are not interchangeable with this fitment.
The P21W is an ECE-standard bulb, meaning it conforms to the Economic Commission for Europe regulations governing lighting equipment, and it sees use across European and worldwide markets.
Because the front and rear turn signals on the CB1100 share the same P21W specification for 2013-2014, a single bulb type covers all four turn signal positions on the motorcycle.
The BA15s base type is not interchangeable with the BA15d base, which carries two offset pins rather than one. Substituting a BA15d bulb into a BA15s socket is not possible without modification.