promised to post pictures of the timing side main bearing conversion of the old engine.
needle roller is SKF "NKI 35/20 TN"
axial bearing is a modified std BSA, I made a bronze ring which is partly inserted in the main bearing bore. the axial setup has worked very well.
converted sometime in 1982~1983, all work done in the royal navy workshop.
hasn't been dismantled since, used regularly for the last 8 years,
total mileage after conversion, my best guess is 12~17.000 km
pictures tell the story.