Whats this new strange noise??

[JayShep1]

So today I decided to change my spark plugs, oil, oil filter etc. After replacing the plugs I fired up the z just to see if there were any improvements... When i put my foot on the gas and started reving, as the rpms would decline the z starts this weird ticking noise. It kinda sounds like when you put a baseball card in bike spokes. I have a video of it, sorry the sound quality isnt the best, but just listen for the sound as the RPMs drop...
http://youtu.be/8JLFimncAyU
If you had any idea of what this sound could be, or anything I could do that would be great...