View Here : Bmw 650 Sound
The ticking sound isn't the air flow but if the box is somewhat open it might be letting a sound out( probably a lightly tapping valve) that you didn't previously hear. Also if there is a gap somewhere in the air box reassembly you will hear some strange sounds when accelerating and decelerating.
The BMW C 650 Sport scooter turns even a routine journey into a memorable riding experience. It is the perfect companion for anyone who is looking for a smart way to get around in the city.The powerful 60 hp (44 kW) two-cylinder in-line engine, which boasts a top speed of over 112 mph, allows you to get from A to B quickly and comfortably.