Honda Motorcycle VTX1800T front and rear turn signal bulbs use a PY21W size. The replacement chart covers 2007 to 2008 production years with 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 VTX1800T uses the PY21W bulb type across all listed positions and model years, covering both the front and rear turn signals for the 2007-2008 model years.
The PY21W is an ECE-standard bulb, meaning it conforms to the Economic Commission for Europe's lighting regulations, which are applied across European and various worldwide markets.
PY21W bulbs produce amber light natively, as the glass envelope itself is tinted rather than relying on a colored lens to achieve the amber signal color.
The bulb operates at 12 volts and consumes 21 watts, which is a standard wattage for turn signal applications in motorcycles and passenger vehicles.
PY21W uses a BAU15s bayonet base, which is an offset single-contact base. The offset pin placement distinguishes it physically from the visually similar BA15s base, preventing incorrect bulb installation.
Because the BAU15s base is offset, a standard BA15s bulb cannot be seated correctly in a BAU15s socket, making the two base types non-interchangeable despite their similar appearance.