Yam's are notorious for not being able to stop on the ramp at all, when loading on trailer, or belt will slip and burn. Never had this problem with a Polaris or Doo, but dealer told me never to stop.
Learned the hard way after burning a belt. I always "walk" my sled up the ramp or pull and pull till I get it on.
Never try to ride it up unless I have a running start on snow, even then it's dangerous if you hit the edge wrong you'll put your ski's out of alignment.