very often, the yamaha part number contains the standard bearing number. So Yamaha's 93306-20589-00 is a 6205.
info from one of my previous posts:
I use Timken or Fafnir collar lock for that and the jackshaft. I think it's about $24. this is the part number for the drive shaft: rae25rr . fyi, the one for the jackshaft is rae25rrb (rounded outer race). Make sure you get metric ones... the other appears to fit, but it's a little too big and comes loose (learned by accident). With the collar lock, you don't have to worry about the set screws letting go. I ordered mine from the local Canadian Bearings store, but do a search online for other dealers.