I've read similar threads with bikes experiencing this similar noise. I got a 2012 Rzr S, 45 hrs, i have been hearing this noise for a while now. At idle it has a metallic knock that sounds like its coming from the engine, but as soon as you idle it up it goes away. It hasn't gotten any worse and i just did the 2nd oil change and the oil was clean. i have read that it can be the clutch weights making the noise at idle. It also doesn't do it immediatly when you crank it up, just after it warms up. Am i being paranoid or is this a common issue?