Good afternoon, not sure if anyone else has had the same issue with their cforce atv but just recently I've noticed a wierd whining noise coming from the transmission of my cforce 400 when you give it gas, you could also hear it when accelerating in low and high gear as well. At idle it goes away. I took off the clutch cover to examine the belt and bearing and they look normal (as in it has no noticeable damage nor dust). I've attached a short video for demonstration if anyone has any idea to what it might be

[2015 Z Force 800 53/Trail EPS]

Man those 400s idle high. If it has never done it before and just started I'm inclined to think its clutch or belt-related. If it were mine I would pull the cover, then run it a bit faster to run the belt up the sheaves a bit to see if it stops at a higher RPM. If it does, I would then measure the gap between the belt and primary sheaves to ensure its correct..then remove to inspect the overriding clutch/bearing because if it does quit when the belt is off of it, it's likely that's the problem. They do fail pretty often.