I have a 2014 YZ 450. Was racing this weekend and when first started the bike would miss and flutter then usually clear out similiar to a two stroke when first started. As the day went it started doing this more and would not idle when doing this. I could turn the engine off then restart it and would run great...was not very predictible on when it was going to act up. I eventually called it a day when I was on the track and was at approx. half throttle and the thing acted like it just ran out of gas. Coasted to the side of the track kicked it and bike started up and ran fine all the way back to the truck. Any thoughts or suggestions is greatly appreciated.