Is this using the beefier battery and the 70t spur? How many teeth on the pinion?
It's odd that the gear fit varies on one side of the gear versus the other... That seems indicative of a malformed spur gear. Any chance you have calipers and can check the roundness?
ive ordered 3 spur gears. i stripped the orginal, installed the 70 which stripped, then ordered a new 70, installed it, stripped it. i have one stock one left that is also brand new from a main? im thinking maybe one of the bearings it sits on is out of true or maybe its the motor shaft that could be bent? yes pinion is stock and this is on the 2250 100c battery