Spark plug questions

Hi,

I rode my 1973 850 about 1100 miles last weekend to Barber and back. The bike ran great although it kicked back a little when I started it before the return trip like the ignition (Boyer MkIII) was too far advanced. I hadn't touched anything that would affect the timing and the battery should have been plenty charged from cruising 79-80 on the interstate.

I went to start it this week it sounded kind of clattery. As though from the left side of the engine.

I checked out my Norton belt primary and it looked okay. The left sparkplug seemed
to just be finger tight, although the threads looked okay at first glance. I pulled out the right plug and the screw on terminal thing was missing. I thought it might be stuck in the wire, but I took it apart and didn't see it.

I wonder if I could have been running it like that? The right plug looks a fair bit hotter than the left, but I don't see any tiny balls of metal on the plug. I would think this would have retarded the ignition on the right side.
Lefy
Right
I seem to recall reading that, in the Battle of Britain, RAF pilots put a gap somewhere else in the ignition wires between the magneto and plug to make more power.

The only time í've had kickback with my Vape-Wassell non-digital EI (basically like the original Boyer EI's) was when I fiddled the EI stator a little to get what appeared to be closer to the 31 deg BTDC on timing gauge. But after a few kick backs I backed it off a degree or so and never reoccured. Do not forget to confirm accuracy of the gauge on primary cover, mine was out about 1-1.5 deg.