Im all for blocking off or removing the AIS systems, I've always taken mine off and found everytime that the engine runs a lot smoother, and throttle response is much crisper without them.
The AIS only works when the engine is cold, and the CAT only starts to work when it reaches approx 400 deg F ((which doesnt take long) normal operating temp is around 1400-1600 deg F)
IMHO most riding is done with a hot CAT, so there really isnt much need for a AIS system or EGR system, which is essentially the same thing.
Most "popping" is caused by over fuelling, when unspent fuel is not ignited until it exits the combustion chamber, this happens more often on carb'd engines, but can happen on injected engines if not set up propperly, this unspent fuel is supposed to be ignited in a slow controlled burn by the CAT (hence why it has a high operating temp, to ignite the fuel)
Hope this clears things up a bit :thumbup:
