On topic for once! Piaggio lack of sparks

I acquired a 50cc Piaggio Sfera for my daughter but for one reason or
another she won't be riding it so I'm selling it.

A chap came to see it and it was all fine, ran as well as it always has, we
agreed a price and he said he'd come back yesterday to pick it up, but
because the gods hate me it wouldn't, and still won't, start. No sparks. It
tried to go four or five times over the next hour or so but now there's feck
all.

I've tried different plugs, cleaned all the earths I can find, found that
there's 12v on two of the cdi unit's connectors when the ignition's on, but
that's as far as I can go because I haven't got a manual for it and I don't
know how to test the coil with a meter. Any ideas how/what to test? The
coil's only got three wires on it, which are green, white and red as you
might expect.

Si

 

T'ain't got one. You do have to pull a brake on before it'll let you use the
leccy start but that works ok, and the kickstart always worked without using
the brake anyway.

Definitely lack of sparks - tried with/without plug, with/without HT cap
(just under 5Kohm resistance), tested HT lead...

Call me a big girly poofter but I really don't want to put a finger on the
HT lead/plug to see if there's anything there at all.

Oh, and I can't get the generator cover off because the screws are made of
edam.

Bollocks to it; £21 worth of Indian scoff ingredients has just turned up -
playtime.

Si