More on cam timing

Having managed to persuade this machine into life, I’m more than happy with the current state of cam timing with the motor, but still the reasons behind it not working are puzzling me. As far as I can tell, the cam wheels are common to the whole range over a number of years, though there was a change in tooth form early on in order to quieten the engine. There’s no evidence in the manuals, guides and handbooks

I have to suggest the cam timing marks on the cam wheels are different either, yet this must be the case or the engine would have worked on the standard timing. Despite inspecting the cams and wheels I have, and matching them to the numbers in the parts books – yes, I know, such things don’t always add up – everything should work, but doesn’t. So, if anyone can offer a suggestion then I’d like to hear from you.