As Pete says, the AF ratio is measured with a sensor inserted in the tailpipe. If the AIS is connected, it will bleed fresh air into the exhaust under certain conditions which will kid the dyno into thinking the AF ratio is too weak. However, what makes it worse for building a PC map is that the AIS won't bleed air in all the time, so the dyno AF ratio readings will be very erratic and thus, so will your map.

The only way to get the right data is to block the AIS.

The bike's O2 sensor's readings are only used by the ECU in the closed loop, plus the bike's ECU knows when the AIS valve is open and when it is closed and can read the lamda signal accordingly. The dyno can't do this and will just read a sudden rush of weak AF ratio in the exhaust when the valve opens and a spike of richness when it closes; in other words it won't have a clue what's going on!

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