Recently purchased a 2009 Polaris sportsman 90 4 stroke atv. Last week it was at Polaris dealer, it had a new carb, piston and rings installed. After 2 minutes of riding the timing chain cover fell off and I discovered that only 1 of the 3 timing gear bolts remained in the cam. 1 snapped off and 1 came completely out and is I’m assuming in the bottom of the motor. Is there anything that would cause this besides it not being torqued to specs or assembled correctly? Thanks