It's like Canyncarvr say's, the rubber damper bushings may be out of place. After the first big crash on mine, I thought that I had bent my bars. After looking more closely at them I discovered that they were not bent. My next suspect was that I had bent the lower handlebar clamp. But after removing them I found that they were not bent either. That is when I discovered that the washers were bent and the rubber dampers were out of place. After straightening the washers and resetting the dampers, everything was good as new. This is a chronic problem that may be solved with a one piece upper handlebar clamp like canyncarvr suggested. I have not tried the one piece clamp, but I do know that one of our team bikes, which is a KX250, has the one piece and has never experienced this problem.
If you are out on the trail and this happens, simply stand in front of the bike, hold onto the handlebars, turn the wheel as far to the side as it will go, and then pull on one side of the handlebar and push on the other side until it is straight. This will enable you to keep riding the rest of the day.
Bottom line is... you could SPEND A LOT OF MONEY on bars and still have to straighten the washers and dampers every now and then... or you could just straighten the washers and dampers every now and then at NO COST.