How to check a Flywheel Magneto?

Jason Sankey /

I am attempting to find my spark-o-hope on my 1980 Vespa Grande. I am almost positive there are shorts in the system. So i am trying to work from the inside out. Does anyone know a good way to test and see if the flywheel Magneto is proving power to the HT coil when the bike is being pedaled?



Re: How to check a Flywheel Magneto?

Bruce Wilkinson /

Remove the sparkplug. Hold the metal part of the plug ( still attached to the HT wire ) against the clyinder with a rag or glove and get a friend to pedal. Watch for a spark fron the sparkplug gap. You may need to do this in a dark place to see the spark. bruce

Re: How to check a Flywheel Magneto?

Jason Luther /

but working from the inside out.... unplug the wire coming from the magneto to the coil, and connect one end of your tester to that, and the other end of the tester to a ground (pretty much any bare metal surface on the engine). by tester, i use a multimeter set on the lowest ac votage parameter. you wont get many volts, but if its moving you are probably okay (as far as the stator plate is concerned). most likely cause for no spark is a bad ground. the kill switch and sometime the lighting circuits (blown balb and such) interupt the ground, thus killing the spark. starting from the inside out is fine, or from the outside in, never start in the middle :)

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