Solution
The Solution to Most Magneto Problems
The vast majority of magnetos I repair were made during the post-war years from 1945 - 1962 so these magnetos are between 50 and 70 years old. Many of these magnetos have never been restored before so it is remarkable that they have any life left in them at all.
The materials available for rebuilding armatures today are better than those available when the magnetos were new. The main problem with old magnetos is a substance known as 'shellac', a natural substance made from the shellac beetle, which was used to insulate the armature windings. Capacitors were also made from natural substances, mica, film and occasionally shellac. Natural substances deteriorate in air. Fluctuating temperatures and humidity levels accelerate the deterioration until the insulation fails and the capacitor plates and coil windings start to short out. We should also remember that most of our classic bikes have been through a period in their lives when they were virtually worthless and many were left in damp sheds or outside under a sheet, yet some of the magnetos are still functioning (perhaps not very well) after periods of neglect and abuse.
By replacing the armature windings and capacitor with modern components, wire, and insulation materials it is quite reasonable to expect your refurbished magneto to last for another 70 years!
It really is that simple and surprisingly inexpensive----->
The Solution to Most Dynamo Problems
Dynamos give problems for a variety of reasons. They don't like vibration, grease / oil / dirt, and they don't like to be overworked. Most dynamos I deal with were made by Lucas in the 1940's - 60's and, unfortunately, most owners don't do any service work on their dynamos until they have failed, by which time damage has usually been done! Many problems can be traced back to the original bearings which were 'open' i.e. the grease was exposed to the environment. Consequently, over the years, the grease either dries up or runs out, giving rise to a variety of problems most of which lead to armature failure. The regulator is also responsible for some dynamo failures, particularly if Mr. Enthusiast has been tinkering with the wiring! Regulator failure, associated with amateur wiring, can cause the wiring in the dynamo to overheat and short out the armature or field coil - burnt shellac has a distinctive smell which most of us would probably recognise! Nearly all dynamo parts are readily available but the dynamo must be assembled carefully to avoid preload on bearings and components working loose resulting in vibration.
New armatures, field coils, bearings and brushes are readily available (at the moment!) so it is possible to rebuild a dynamo 'as new'. If your dynamo is giving trouble and you are thinking of having it refurbished you should consider whether to convert to 12 volts.
12v conversion explained ---->