We rebuilt the motor, new Hot Rod Crank and Vertex 13.4:1 Piston Kit, Valve Seats cut, new valves, new Hot Cams Gold Series Stage 2 Cam with head slotted for cam, and also a Rekluse Clutch. I run VP U4.2 fuel. The bike runs strong all the way to the line, we shut off engine until last minute. This is at Budds Creek, when he would leave the line and run around the track it was fine but there is a huge hill to climb, old finish line hill, it would cut off everytime at the top and won't restart. With the Rekluse you can't push start so he would have to push it back everytime. I had a fuel filter before the carb and removed it, same result. Could it be vapor locking? This bike hasn't made it around the track since the rebuild. Any thoughts?