Suzuki Motorcycle ALT125 Tail Light Bulb Size

The Suzuki Motorcycle ALT125 tail light utilizes a specific 81 bulb size for illumination purposes. Data for the mentioned component covers the period from 1983 through 1986.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1983-1986	81

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 8W.	81

Additional Notes

The Suzuki Motorcycle ALT125 uses the 81 bulb for its tail light across the 1983-1986 model years.
The 81 bulb follows the ANSI standard, which governs bulb specifications in the United States and Canada.
This bulb operates on a single filament, meaning it serves one lighting function rather than combining, for example, tail and brake light duties in a single unit.
The 81 bulb uses a BA15s bayonet base, a single-contact fitting where the bulb is inserted and twisted to lock into place.
At 12V and 8W, the 81 bulb draws relatively low wattage, consistent with a dedicated tail light application rather than a high-output stop or driving lamp.
The BA15s base is not interchangeable with the BA15d base, which carries two contact pins instead of one, so substituting a dual-contact bayonet bulb in this application would result in an incompatible fit.