Starter problem

75 Commando with a Dave Comeau starter, new engine sprocket, starter gear and sprag from CNW. Good battery. It was working /starting the bike. Started to "click" a few times when I hit the button, then the starter worked. Now it sounds like the starter is spinning but it is not turning the motor. Could it be a stripped gear? solenoid ?

Your sprag is slipping. Not the first time ive heard of newly fitted sprags starting to slip (pardon the pun).
You need one of my roller cam sprags.

Ok, i did not sound like slipping, it is a new CNW sprag anssprokrt

Try pulling the bike backwards with the bike in gear and check the sprag and starter drive train turn the starter motor backwards (you should be able to hear the starter train turn) Take the plugs out to make this easier. report back. CNW sprockets and sprags are still prone to sprag failure (slipping etc) as much as the AN sprockets,sprags,drive gear. The dog bone sprag is too fragile for this application. I'm of the opinion that when this system was designed for the Mk3 in 1975 they had to use what was available (off the shelf so to speak) Hence the use of the cross and morse 14 tooth dogbone sprag. These might work ok as a conveyor anti run back clutch, or a backstop. They are working at the limit as a starter motor clutch fastened inside a very vibratory engine.

OK, I’ll try that tomorrow .
I’ll still pull the cover off tomorrow and look at all the gears make sure nothing‘s not stripped.

It could be you've blow the kick back protector gizmo. Starting with too much oil in the sump after sitting a few wks btwn rides will place a lot more load on the starter components and risk the sprag and or the kick back protector. There is an OldBrits article floating about in older threads here describing how to set the correct 50 ft-lb torque limit on the KBP.

But, if it is the backfire device you should hear the clicking as the balls pass over their detents, no?

Yes it should make a loud rattling noise if the anti-backfire device is slipping.