AJS & Matchless Owners Club

Hi all. I'm new to magnetos and have a couple of questions. Firstly, when I operate the advance/retard lever, should I see any movement of the points plate? Secondly, is a slack cable fully advanced or fully retarded? Thanks.

The steel camring which is outboard the points in the allloy housing should move relative to the points backplate as you advance and retard. The backplate won't move if the mag is on the bike.
If the cable enters the mag end housing on the left (engine side), looking at it from the points end, then the camring is advanced when the lever at the bars is slack (pushed forwards fully) - pulling the lever will retard it. (This would be with the 'normal' parts and with the lever on the left-hand side of the 'bars.)
The camring is operated by a plunger attached to the cable - which you can't really see properly when things are assembled. Sometimes they get jammed, seized up or otherwise deranged . . . either owing to cable trouble or misalignment/corrosion/plunger trouble at the mag.

Thanks Groily.