Brightspark Magnetos

Set  the timing of the ignition in accordance with the machine's handbook.

Twin- and multi-cylinder magnetos:

• Having set the timing with the points opening on one cam lobe, you should check that it is also correct with the points opening on the other cam lobe. This is best done using a strobe.

• If the timing is not correct on both lobes, the reason could be that:

  • the contact-breaker assembly is wobbly on the end of the armature;

  • the cam is loose in its housing;

  • the armature is loose in its bearings;

  • the cam or its housing were incorrectly machined (rare);

  • the cam has worn unevenly (rare);

  • with ring-cam magnetos, the armature and cam are not coaxial due to the outer race of the bearing at the contact-breaker end not being seated properly by its insulator in the cam housing.

• The last of these possible reasons is very often the cause.