Will be trying to start my 1940 M20 within a few weeks. I have turned over the engine but cannot see a spark at the plug or at the points. It was ridden into a shed in 1968 and has not been fired up since.
I have not touched the engine apart from fitting a new small end bush, doing the valves and refitting barrel and head with new gaskets. Magdyno looks dry with no rust visable.
What process should I follow to find a spark?
All answers appreciated.

email (option): araine11@hotmail.com

Easiest option to see if the mag is working is. Check the points gap is about 12 thou. Run a small piece of fag packet between the points when they are closed to clean them and then give the bike a good kick with the plug resting on the engine to earth somewhere. A good mag will give a healthy spark every two revolutions. Maybe the plug is duff, so try another one. Ron

email (option): ronpier@talk21.com

Take a few minutes to make this little tool:


Clamp it to a fin of the barrel, 'kick' the engine with your hand and you can see the spark from near by, even in bright daylight, and without the risk of an unpleasant shock...
The small bulb is not used for this but is handy to test your circuits.

email (option): viaconsu # planet dot nl

Thinking ahead what normally goes wrong to cause a magdyno not to produce a spark?

email (option): araine11@hotmail.com

The main problem is usually the condenser, buried within. It will usually start the bike from cold but not again when hot. The coil windings can break down also. If in any doubt, get it overhauled by an expert. It's just not worth the heartache having a duff mag. Ron

email (option): ronpier@talk21.com