Just ran my '16 M8000 Ltd for the first time this weekend - definitely noticed the same noise you're describing - kind of a chattering noise.
Checked out the primary this morning - everything looks fine - just run her I guess.
The Carlisle belt is a bit longer so you need to adjust the deflection to compensate for the longer belt.
Accomplished by adding or removing the shims under the retainer that holds the secondary clutch on.
Carlisle XS809 worked for me - blew two belts in the first two hundred miles - now have over 800 on the XS809 - and still looks great.
Just have to adjust belt deflection and it's been working fine since. Have all the same evo stuff as you plus a few other goodies.
Was there yesterday - it was rock hard all day - put our scratchers down and left them down for most of the day - trail was quite rough and extremely hard. Only positive thing was it was snowing when we left.
The XS809 works awesome - and I know of quite a few guys using them - with great results. I was in two and a half foot deep powder all day yesterday with some very high underhood temps and this belt just keeps taking it. Now have over 700 miles on it after blowing two cat belts in the first two...
Carlisle XS809 - I've got 650 miles on it now and still looks like new. Blew up two Cat belts in the first 200 miles.
Half price of the Cat belt as well.
Was out today - some decent snow through Broadview - but still need some more to fill in the runs through the meadows - still need to be careful.
Definitely lower snow levels than last year at this time.
26x9x12 front
26x12x12 rear
2 inch lift
1 inch wheel spacers in the front
1.5 inch wheel spacers in the back.
Nice stable ride with 12.5 " on ground clearance
Smoother ride as well with the radials.