Honda Motorcycle XL350R front and rear turn signal bulbs utilize a P21W size, with rear signals also compatible with 1073 bulb specifications. The replacement chart covers 1984 to 1985 model 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 most frequently specified bulb across the Honda Motorcycle XL350R turn signal positions, appearing in three of the four position-year combinations listed.
The P21W operates at 12V and 21W, follows the ECE standard used in Europe and worldwide markets, and uses a BA15s single-contact bayonet base with a single filament.
The 1073 follows the ANSI standard used in the US and Canada, operates at 12V and 13W, and shares the BA15s bayonet base with the P21W despite belonging to a different standardization system.
The 1073 is a lower wattage variant of the 1156 bulb, drawing 13W compared to the 21W of the P21W, which means the two bulbs are not electrically equivalent even though both use the BA15s base.
Because the P21W and 1073 share the BA15s bayonet base, one will physically seat in the socket intended for the other, but the wattage difference means substituting one for the other may affect turn signal flash rate or circuit behavior.
On the Honda Motorcycle XL350R, the front turn signal position used the P21W for both 1984 and 1985 model years.
The rear turn signal position changed from the 1073 in 1984 to the P21W in 1985, making the rear socket specification year-dependent.
The 1984 XL350R is the only model year and position combination in these specifications that calls for the 1073 bulb, specifically in the rear turn signal.