After a recent magneto refurbishment I have refitted the magneto and auto advance unit on my 1959 Gold Flash. Part of the timing procedure is to turn the bridge plate of the auto advance to expand the bob weights against their small spring tension and then wedge the unit in the fully advanced position with a small bit of wood before placing it on the magneto shaft. I think I have followed the procedure for ignition timing correctly but when I removed the wooden wedge after tightening the bolt on to the magneto shaft the advance unit did not move and remained in the fully advanced position. I was expecting the bob weights to move inwards under the tension of the small springs as they do when the unit is not fitted on the magneto pinion.
Do I have a problem, or is it correct that nothing should move when the wedge is removed. All instructions I have found just say don't forget to remove the wedge, but no comments on what should or should not happen when I do.
bob weights and aau should move freely and return under spring tension, do they return if you move them by hand?
I presume the bob weights moved smoothly before the unit was fitted to the magneto?
If so then probably nothing wrong here.
The bridge plate is connected to the mag armature which apart from its own weight (about 700 grams) is under the influence of the magnetic field of the body and friction from the points cam on the moving point heel, in the bearing, the oil seal and pickup brushes. The small weak springs cannot overcome this in the static position. They are all like this.
But when you kick it over you will see it return to the retarded position and when the engine is running it will advance and retard as designed.
Mine on my A7 does that but as Julian say's it works perfectly OK when running or starting.
Thank you all for your helpful advice.
The bob weights moved smoothly before fitting. Now the magneto and pinion are fitted, the bridge and the bob weights do move and I can advance or retard it by hand. It's quite stiff but if I am moving the magneto armature at the same time that seems reasonable. I have operated the kick start a few times with the plugs removed and the unit is fully retarded now so it all fits with your descriptions of what should be happening. I will replace the timing case cover and move on to the next job.