Are all brushes for this magneto all the same or was there variants. Just eliminating a lack of spark on a new barn find that has been hiding since 1989.
As far as I know all the Lucas mags use the same brushes. Run a mag file or a piece of fine wet and dry between the points. They may have a scale build up due to lack of use. If that fails damp may have got into the armature windings or the condenser.
Will a heat gun help ? Did the points. Will look at pick ups in the morning. Thanks.
Check the armature earthing brush and the brass armature end beneath and clean if necessary. Can get oil there if the seal is worn or damaged.
If steel points backplate make sure the spring is not touching the cam ring and shorting.
It's the manual advance and retard with a push button kill switch. There seems to be a clip it touches. That was to one side ? not in the middle.
Cleaned a few joints and now have a bright blue spark.