Only time mine would not start was after leaving it outside for a week or two with a cover, after riding it. loaded into truck one moring fine, would not start at sno park. I suspect condensation in the ecu or somewhere. fired up after sitting in warm shop couple days, never happened again, I try not to leave it outside for extended periods now.
Also the one time I ran it with ethanol fuel it was noticeably lower idle, wont touch that stuff again. I suspect a common trait you might find with people having these start issues is either leaving sled outside and/or running ethanol fuel. I rarely let my sled idle completely down before shutting the motor off. seems to fire up best when its still idling a little high after a pull and you shut it off. they run so rich when idled down, usually requires a crack throttle to fire first pull in those cases, maybe just mine. They do have different fuel mapping between the years I believe.