I finished tearing down the motor out of #410 this weekend. Everything looked decent. Clearances on the bearings were getting kind of high and rings weren't sealing in the cylinder. The one problem I did find was the at the rear main cap. I pulled off the cap and inspected the crank journal and bearing. The cap side of the bearing had a groove that could be felt with my fingertip. The crank looks pristine.
I'm assuming that the bearings are much softer than the treated crank journal and this is the intended failure mode - bearing craps out and spares the crank.
I mic'd the crank journal 4 places across its length and there is no abnormal or uneven wear, no scratches, no grooves. Is there anything to worry about or is the crank just fine?