We my wife and I were on a ride through the mountains in West Virginia and decided to ride Sky Line Drive home. I came to a stop sign uphill making a left turn uphill. There was a center curb with the stop sign. I was positioned on the left tire track to the inside of the turn. When I started to move I wasn't paying attention and didn't have enough throttle on, the engine started to clunk. I disengaged the cluth planning on getting some RPM's rev and keep moving. As soon as I pulled the clutch we started to roll backwards - towards the center curb. I grabbed the brake and went to put my left foot down - no ground there. I held the brake, we went over to the left, my wife doing a perfect left rear parachute landing fall (head over heels down the curb). Everything was fine, we were not hurt, the Ultra CLassic has a small scratch in the chrome on the bag guard. Lesson learned - position yourself to the outside of the lane opposite of the turn to stay on the high side of crowned roads and away from center curbs.