I think i remember some of the key way holding the pully and motorshaft were bit small, this may becausing the sound.
"sent the vid to Zero...had me take it in... replaced front sprocket and woodruff key set under warranty. they were agreeable."
Suggest you also send video to Zero.
while accelerating or deccelerating it be pressed hard against the shaft or pully , but while coasting may be alternating between them both causeing clicking.
or a loose pulley, set screw may need tighnening.
This link shows keyway and set screw locations / examples.
http://www.gatesmectrol.com/mectrol/brochure.cfm?brochure=5247Also posting this in the zero forum will get more responses / reads
