First of all... to XT660.com!

The popping and banging is perfectly normal on all XTs. It is the Air Induction System (AIS) doing it's bit in cleaning up emissions to keep the EU greenies happy. Basically the ECU controls a valve which allows fresh are from the airbox to be drawn into the exhaust ports just downstream of the exhaust valves on a closed throttle. The idea being that the introduction of air will ignite and burn off any residual fuel left behind after combustion with the result being cleaner emissions and... some small explosions! This all sounds louder and more noticeable with aftermarket cans fitted.

You can stop the popping and banging if it annoys you quite easily and (the best part) without spending any money! Read this thread for details.

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