I need a little help. I am rebuilding my new yz due to a blown stopper lever bearing and have split the cases to clean out the debris. I did not remove the crank from the left side. After rejoining the halves, I put the drive gear assembly back in the following order: Thrust plate, drive gear with the thicker projection inward, governor gear, plain washer, and then the nut. My problem is that when the thrust plate clears the splines on the crank, I cannot figure out what keeps the thrust plate centered on the shaft, as it is grooved behind the splined segment of the crank, and the thrust plate sits over this grove. It also seems the crank seal is a bit proud of the case and reluctant to seat further, but this doesn't affect the thrust plate.