First off thank you for reading my post. I have a 2012 yz450f with approximately 70 hours on it. Never had an issue before. Bike has fmf slip on and tuner since the bike was new. Went to a practice tonight and after about 6 laps the bike died in the air either when I was in the air or on the landing. After doing this twice I decided to exit the track. Went back to truck and took all internal parts out if kill switch. Went to track with smaller jumps and no people to land on me and it did it again on jump landing. Went back to truck and completely unhooked the kill switch. Went back out and it did it again. Fuel tank was full at start of ride. If anyone has had this happen or has any ideas. It does not do it on acceleration or braking. Only on jumps so far. Thank you for reading my post i know it is kinda long.