You are correct Ian I forgot about that seal.
I have given the dynamo a good clean and reassembled it. I redid the Ohms test with the dynamo fully assembled and go a reading of 3.2 Ohms. All good he said to himself. I them tried to turn the fibre gear in case it was slipping buy using a large screw driver through the opening where the dynamo goes but it would not turn. I placed the dynamo back in the bike and fired it up checked the voltage at the dynamo and still only got 0.5 Volts.
I know there must be a problem with the oil seal in the timing case but, I am just trying to get the bike going for this weekend as it is the All British Rally at Newstead. Then after next weekend the whole bike will be dismantled and rebuild for the International Rally in November.
If I was to test the dynamo on the bench for voltage what RPM can I run it at.
Any suggestion on where I go from here would be appreciated.
If you get two wires joined at on end, put one end in the D socket and one in the F socket. hold on to the side of a 12 volt bulb the end of the bulb hold against an earth point on revving the engine it should light the bulb. If this doesn't work I think you are looking at another armature for the dynamo.
A battery powered hand drill may rev sufficiently to get the dynamo to kick in. However, you may need it to revolve a little quicker. Don't rev the dynamo for too long though as you have no way of regulating the strength of the field coil.
Also, have a look at BSA Technical Sheets 808 and 808A (808 is negative earth and 808A is positive earth). I can't say that I have paid any attention to the brush location on these two wiring diagrams, but they do seem different (F still goes to F and D to D). I was going to ask someone like Noam why they would differ.
I have been trying to get my small mind round which wire goes where on my field coil for an E3L as I have no way of distinguishing which of the two wires go where (i.e. which one goes to F and which to earth). They are both cut short and both black!