A motor cycle incorporates a sensor detecting a condition of the tire, such as,
for example, tire pressure. A transmitter transmits the tire condition and a receiver
receives the tire condition. An indicator indicates the tire condition. A battery
supplies electric power to an engine of the motorcycle, the receiver and the indicator.
A control device controls the power supply to the engine, the receiver and the
indicator from the battery. A main switch assembly and an activating switch, which
activates the receiver and the indicator, are interposed between the battery and
the control device. The control device allows power supply to the engine, the receiver
and the indicator when the main switch assembly is turned on. The control device
also allows power supply to the receiver and the indicator when the activating
switch is turned on. In some arrangements, the activating switch is automatically
turned on when another sensor detects a condition change of a frame assembly of
the motorcycle.
