reg, as I know, belt shouldn't touch kick start half moon, bendix or cvt cover.
maybe belt pieces was flapping inside making marks everywere before it snapped. happened to me twice
took me half an hour of cleaning the pieces and sticky black dust
my advice:
-buy quality belt
-clean and lubricate torque driver for smooth operation regulary
-clean inside of cvt cover and variator system. you don't have to be thorough. compressed air works for me just fine
-when installing belt and tightening front variator nut, rotate variator a couple of times after tightening. 4 or 5 times should be ok. it's making belt to sit propperly
-check belt condition at regular basis. when removed, twist the belt inside out. if you see deep cracks between belt teeths, it's a sign the belt is at the end of a life
I hope this will help