Ok I am at a loss here!!! I thought the AIS pumps cool air into the heads to burn the fuel cleaner (lean)to meet emmisions and by disconnecting it the fuel doesnt burn as well (rich). amd I backwards or what?
The AIS allows air to be pulled into the exhaust port during the low pressure pulse that is created after the exhaust begins moving down the exhaust pipe. There are one-way valves in the AIS system so exhaust under pressure isn't pushed back through the system. If those valves are leaking the pipes leading to the heads will be very hot to the point of things starting to melt.
The extra air (oxygen) injected into the exhaust stream ignites any fuel that wasn't burned during combustion thus lowering HC
(unburned hydrocarbons) emissions. Because of this the exhaust temperatures with a working AIS will be hotter than without.
On the carbureted engines it is the primary emission control while on the FI engines it is secondary and is used to ignite unburned fuel when the engine is richer during cold starts and bring the catalyst up to its operating temperature quicker, it continues to work though in order to take some of the load off the catalyst. It works best at idle and as with the pulse air systems that used to be used on cars somewhat less as engine speed increases.
It is supposed to be disabled during high vacuum deceleration and low vacuum heavy acceleration.
On a carbureted bike the AIS has to be disabled before checking the AFR. On FI bikes it's a different procedure altogether.