The ignition
system has its faults, but is generally as reliable as any electronic
system that's up to 30 years old. Typically the faults occour in one
of three areas. The alternator rotor can become demagnitised and at
the very least this results in poor starting and most likely poor
charging as well. The high voltage winding the alternator stator can
also break down, which usually results in missfires particularly at
high rpm.The potting around the pickup coils tends to crack with age
and the coils can fail. Lastly the ignitors can fail (Morini call
these transducers).
The rotor can
be remagnitised.
The stator can
be rewound.
The Pickup is
probably best replaced, although they can be rewound and repotted.
Ignitors are
readily available, but are really quite simple;
Apart from the SCR, these are
the component values as actually measured from an original ignitor.
The values of C2 has been misquoted elseware on the web. Smaller
values can give difficult starting, although it does depend on the
coil. The value of C1 as measured appears to be 820nF, although 100nF
seems to work just fine. The circuit is used with an external coil.
Either use a coil specified for use with a CDI ignition or use a 6V
coil. I got a pair of coils from BTH Magnetos.
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