Originally Posted by Kev

A BIT OF BACK ROUND

AIS :air induction system burns unburned exhaust gases by injecting fresh air into the exhaust port , reducing the emission of hydrocarbons.
When there is negative pressure at the exhaust port the reed valve opens allowing secondary air to flow into the exhaust port.
The system also has an cut off valve that is controlled by the signals from the ECU.The cut off valve opens to allow the air to flow during idle and closes to cut off the flow when the moto is being driven.
However,if the coolant temperature is below the specified value the valve remains open and allows the air to flow into the exhaust pipe until the temperature becomes higher than the specified value.
Also if you unplug the AIS there is a mechanical function as well, where it drags in air when there is a vacum in the exhaust. e.g. on R1 and other yam bikes they disconnect the hoses and block the holes.