Being new to the Norton marque I have to ask perhaps a somewhat naive question concerning the Lucas auto magneto. Due to my difficulty of swinging the kickstart over and the occasional back firing I intend to check the ignition timing using a degree wheel to 38 deg btdc.
However, I first seek advice regarding the ATD which ‘ perhaps ‘ is sticky in operation. The question is with the magneto on the bike and the inspection cap off, whether I should be able to physically rotate the points assembly from fully advanced to fully retarded and vice versa ? if so approximately what is the rotational angle ?
To work the advance and retard unit through its range you need to operate the weights inside the timing cover. Get a new gasket and pumpseal first.
Thanks Robert .
Further to my query , when rotating the points assembly, the points do not return automatically. I assume that they should rotate via spring pressure from the rear of the magneto. Hence my thought that the auto advance and retard mechanism is stuck through lack of use. I will remove the off side timing cover and investigate.
Its normal for the unit to appear to only partly retard ,I think its the action of the points that inhibits the action when not running.
I have removed the timing cover and indeed the adv / ret. mechanism is very sticky. I can rotate it by hand but the weights remain in what ever position it is left. The two return springs are unable to move the bob weights under their own tension. I assume that the centre hex. head when loosened will enable the mechanism to be removed. I should then be able to hopefully strip it and free it up.
Don't rush into speculating it is jammed. The springs might just not be able to rotate the magneto back against its own magnetic field. Also - where does 38deg BTDC come from? If that is the advance setting, I'm surprised you have not damaged your engine or yourself.
The centre hex should not only fix it in place, but also act as the extractor to draw it off its taper. Unless someone has modified it...do you have a manual?
Please advise what is the recommended timing for a Dominator 99 btdc ?
Books give 32 deg at full advance.
Thanks David .