bad idle and hard to start '72 750

For the last 2-3 weeks the Commando has been really hard to get running and if I let it idle, would die and very hard to get started again. My assumption was this bad gas, but after thinking about it...doesn't make sense both (Amal) carbs would get thier idle circuits plugged at the same time. A light came on (in my head) and I checked the timing. At an idle using a timing light, the mark wasn't visible at all. Reving it to 4000 rpm, it advanced to about 18 degrees BTDC. Reset to 26 degrees BTDC (combat) and it starts easily and idles great. So what caused the timing to slip? Running a Lucas RITA ignition, the magnetic rotor must have slipped inside the camshaft end. Makes sense if it does slip it would retard. Remembering back, I really hammered it in 1st and 2nd leaving a Harley shop a few weeks ago and that was likely when the timing slipped. I may be 58, but still am a kid around a Commando. Any thoughts on my logic?

I've had the two bolt that hold the timing plate come loose. Check that first.

The timing plate was tight. Actually so was the magnetic rotor. Nevertheless the timing was way off. Could be that age "58"....loosing it? Haven't had a chance to run it again after resetting the timing. Will get out next weekend.