I am now able to offer an almost complete dynastart rebuild service. This includes simple repairs such as replacing broken brush holders and lubricator for the spark advance cam to rewinding or re-insulating coils for the field unit.
I also have the ability to have your armature completely rewound if needed.
Another service I have is new brushes that actually were designed for the Isetta's and BMW 600 dynastarts! You may say, I already have brushes that fit the dynastart. I have found through the school of "hard knocks" that the brushes that all the suppliers are selling today are not the same as the original. The carbon composition used in the replacement units today, is not the same as the original. This leads to hesitation on the first rotation of the engine and stalling at the first compression stroke. If you hold the key, normally it will creep over and then start normally. With the correct brushes, this doesn't happen. The engine will spin over every time.
I had a set of original brushes from the 1950's analyzed by a lab at one of the major brush manufactures and also analyzed the replacement unit that are available today. They determined that the composition of these two brushes were not the same. In fact they were able to determine that this difference was causing a higher resistance through these replacement brushes and thus limiting the starting torque of the dynastart. I had them make new brushes based on the 1950's composition. These make a remarkable difference in the starting characteristics of the dynastart.
Below are some pictures of coils I have both made and re-insulated.
Work always has to begin with the dismantling of the field coils. The picture to the left shows a typical field frame with the starting coils removed.
The coils to the left are the starting coils removed from a recent rebuild. These coils were in fairly bad condition with damage to the insulation and other issues.
One of the "other issues" was this insulation had failed on the back side of the coil and the coil had shorted to the frame. This is not totally uncommon.
The coil to the left is a starting coil that has been stripped of its outside insulation and checked for other issues. This coil was reused as shown in the photo below.
The picture to the left shows 4 starting coils that were all stripped of their outside insulation and then re-wrapped with new insulation. After being wrapped, they are dipped in motor insulating varnish overnight and baked for several hours.
These are the above coils after being removed from the oven where the insulation was baked into the coils.
To the left is a typical field unit after cleaning and rework. In this case, the 4 motor starting coils were re-insulated and the 4 generator coils were cleaned and re-installed.
When it is necessary to replace the generator coils, I make those as can be seen to the left. These are not available any longer to my knowledge - thus I started making these coils and they are made better than the original! This is primarily due to better processes that are available today.