CN for the drive side roller has been advised by some other knowledgable people as well.
My "cat among the pigeons" comes in this email I got from John Birch (long time Meriden man and more recently technical man at LF Harris who make most of the new meriden triumph spares available now):
"Pre 1970 the caged roller 70 2879 came in 2 spot which translates to C3 condition and is satisfactory for your application, as TMS stated. Later 750cc after 1979 went to C2 which is graded to the crank journal and the closest tolerance, your crank would not apply."
I'd love to hear any more thoughts on this matter before I toss a coin to decide!
While I'm in uncertain mind, does everyone agree on C3 ball for the timing side, for pre-unit T120?
Many thanks Dave