So the swingarm has a pair of roller hearings on each side or, each half for a total of 4 bearings...and a thrust bearing on each side too.
The swing arm bolt runs through the entire assembly seeing: Frame / Swingarm/ Engine / Swing Arm / Frame
Are there any bushings or bearings in the engine case?
I see something that looks like a bushing in there....is there any more?
Is the hole in the engine just a clearance or is it 'load bearing' to the rest of the whole assembly?