Had my girlfriend out on saturday in Crowsnest pass, this was her first time on a new sled in the mountains. I was with my regular sled pal and she was riding his 600 MC(stock). She was going up a small hill, not very steep, but the snow was and she did not have enough speed through the corner and the sled tipped, she fell off and the sled did a half roll and stopped, but the throttle got stuck wide open. I saw the roll and she was crawling back to the sled before the throttle stuck open and by the time I got there, about 30 seconds later, I managed to dig to the key and shut it off. Coolant spilled out and definately some overheating. The sled drove out to the access road by itself and we brought in the truck to take it the rest of the way out so as to not do anymore damage. She is devastated, but not hurt, and is worried about having to pay for a new engine, and is talking of not snowmobilling again. It will be interesting to see how much damage was done, I hope not much. This is the bad part of letting someone else ride your ride, she did not do anything wrong, but you have to expect that something like this can happen, eventually. Both me and my buddy have done this a thousand times on eachothers sled, with no damage, but this was her first time. She also did the same roll on my sled on the way out but on the brake side of mine, just some flooding.