The root cause of the ovality is most likely over-reving if the largest diameter of the hole is between 4 and 10 o'clock. If the largest diameter goes straight up and down along the center of the rod (between 6 and 12 o'clock), the reason is possibly a tight ABC setup.

If lack of lubrication is the reason, there should be signs of overheating in the bearing bush. (carbon deposits or blue-shine in metal)