After 5 years of searching I finally found a good original firefly coil but still no spark and only 1v AC coming off the alternator despite re-magnetising the individual alnico magnets.
In desperation after re-testing the stator I called an electrical engineer friend. He said that the only way to magnetise a flywheel is to do it in-situ because, as soon as the magnets are removed from the magnetiser, they lose a lot of their strength. I decided to replace them with epoxied in 10mm cube neodymium magnets arranged in pairs with poles NN and SS around the outside. When checking with a compass the needle flips as it passes over each pair.
Spinning with my drill I got 3v AC so I connected the coil and wonder of wonders it began sparking! Now my bike is 100% original.
Cheers Bill
In desperation after re-testing the stator I called an electrical engineer friend. He said that the only way to magnetise a flywheel is to do it in-situ because, as soon as the magnets are removed from the magnetiser, they lose a lot of their strength. I decided to replace them with epoxied in 10mm cube neodymium magnets arranged in pairs with poles NN and SS around the outside. When checking with a compass the needle flips as it passes over each pair.
Spinning with my drill I got 3v AC so I connected the coil and wonder of wonders it began sparking! Now my bike is 100% original.
Cheers Bill