[Lynn Eades]

I cannot remember the part number. It is an imperial bearing, the bore size being 1.000" The Australians saw a bit of common sense and changed theirs to a metric 6305 (standard metric annular grooved) which is what the cam rollers and cam plate pivot bearing is. The metric 6305 is 62x25x19 so the imperial bearing has a bigger bore, and a smaller O.D.
Back to the imperial bearing, it is quite expensive, and hard to find, but as has been stated here, a few vendors in the U.K list them ( not around the rest of the planet) (RM8 = 2 1/2" x 1.0" x 3/4") If you can get a non self aligning bearing in the right size (I think the RM8 is just annular groove) It should work just fine. Phew!
BTW the self aligning bearing is supposed to have the lowest rolling resistance.