Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
I find the correct mark for cylinders 1-4 and set the points gap, all is OK. Then when I rotate the crank for setting the 2-3 cylinders the points for 1-4 are still opening making the gap wider !!
Many years ago my friend had an electronic ignition set which was always going wrong. In the end we took it off in favour of points.
...which you just don't seem to get with the original installation given basic servicing.