The 1156 is the sole bulb type specified for the Yamaha FJ600, covering both front and rear turn signals across the 1984-1985 model years.
The 1156 is a single-filament bulb, meaning it serves one electrical function only, which in this application is turn signal operation rather than a combined stop/tail function.
The 1156 operates at 12 volts and 21 watts, a wattage rating consistent with standard incandescent turn signal applications in motorcycles of that era.
The 1156 uses a BA15s bayonet base, a single-contact bayonet mount with one locating pin on the side of the base, which distinguishes it from the dual-contact BA15d base used on two-filament bulbs such as the 1157.
The 1156 follows the ANSI standard applicable to the United States and Canada, indicating the specification is drawn from North American market fitment data.
Because the front and rear turn signals on the FJ600 share the same 1156 bulb, a single bulb type serves all four turn signal positions on the motorcycle.
The BA15s base of the 1156 is not interchangeable with dual-contact bayonet bases; substituting a physically similar but electrically different bulb such as the 1157 into a single-contact socket is not a compatible replacement.