Some random thoughts which may or may not help:-
- is the carb balance pipe fitted?
Put a blocked off piece of hose on for the balance pipe. Don't exactly remember why but that's what I do.
- are the carbs at least loosly tuned, e.g. throttle cables slack, slides bottoming, pilot mixture 1-1/2 turns out and idle stops turned in slightly?
- any air leaks around the inlet manifolds?
Hard to tell when not running. I was using the fat o-rings but they really didn't fit in
the groove on the carb, more on top of it.
Today I switched to gaskets.
- what do the plugs smell/look like after starting attempts? I would hope that you can at least smell petrol and they arent black/shiny
They look new. Not wet with gas. Everything smells like gas around the bike.
- is the fuel fresh?
- what about battery
charge status, do you have at least 12v and a good earth connection especially to the engine?
13 volts and I believe the earth is good.
- what type of points plate is fitted 4CA or 6CA and what about the AAU springs, is there any slack?
6CA. Should there be slack? I'll look.
- have you double-checked the cam timing, sometimes there is more than one timing mark on the pinions.