The 650ss also suffered from drive side main bearing failure, it was a RHP 'superblend' roller bearing. Strangely there did not appear to be lateral movement in the worn one, probably less that 1 thou of an inch but it made a noise and caused vibration. Also the early 650ss was prone to rods breaking, I had a rod let go on a trip to Snetterton one Sunday,destroyed drive side crankcase I stripped engine and the local dealer (Hallens of Cambridge) sent the undamaged timing side back to Norton who machined a new drive side crank case to match, and new beefed up rods.