Magneto question

Information relating to the Matchless G12 or AJS Model 31 650cc twin
Member
Posts: 12
Joined: Tue Oct 24, 2017 11:05 am
Location: DEVON UK

Magneto question

Postby MalcW » Sun Nov 12, 2017 11:10 am

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.

Member
Posts: 1119
Joined: Thu Jul 04, 2002 12:00 am
Location: NORMANDIE FRANCE

Re: Magneto question

Postby Groily » Sun Nov 12, 2017 11:33 am

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.

Member
Posts: 12
Joined: Tue Oct 24, 2017 11:05 am
Location: DEVON UK

Re: Magneto question

Postby MalcW » Sun Nov 12, 2017 9:31 pm

Thanks Groily.

Return to G12 / AJS Model 31

Who is online

Users browsing this forum: No registered users and 3 guests