Reviving an old thread here, but I thought Id confirm the R1-R4 range on the camshafts.
I recently purchased some parts, all from a low use sandcast engine. The rocker cover was dated 30/4/69, the clutch basket late may 69. It has the early rocker gear and the camshaft which came with it was an R4. Im unsure of the engine number but assuming it was at least a June 69 assembled bike. Pics below (although the R4 is not visible it is confirmed. Ill post a pic when it arrives).
A question for those who have been able to compare R1-R4 cams - Did you notice a lobe difference in the cam profiles between these cams? Im thinking it is possible given the exhaust changed from the lotus root to no number c. 4148, the cams may have been changed accordingly?
