Coil information
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
Created:
Updated:
Thanks to Ralf Brinkmann for sending me this information. Ralf is remembering much of this from an extract of a schoolbook. In Ralf's own words:
Some years ago with my Guzzi I changed to the blue Bosch coil - so last year I gave away all my black Bosch coils to the owner of a BMW-Isetta. I collected these coils over the years when I had air-cooled Volkswagen's - so I'm not able to measure but they all differ a little bit in size and resistance.
But I have a chart for you. The chart compares the black (E), the blue (K), and the red (KW) Bosch coil and shows how fast a modern transistor driven coil loads. In this chart the Guzzi engine would count as 3-Cyl. due to the asymmetric arrangement.
The lower the the resistance of the coil the faster the coil loads up to a definite voltage line - important at high engine speed.
The limit for the breaker points is the 5A line. For this reason the red E-coil needs a fat 1.8 Ohm resistor in series connection. The resistor may be shortened by a relays while starting.
If you want more amps you must use electronic components. Modern Guzzi coils - e.g. Jackal - have less than 1.0 Ohm resistance in the primary circuit.
In combination with the breaker points the powerful 4th coil will need something like this: Steuergeraete fuer Zuendanlagen mit Unterbrecherkontakt und Fliehkraftverstellung
These breaker point driven TSZ-U (or TSZ-K) controllers do not close the primary coil circuit for a fixed angle but for a fixed max. time - maybe 4 ms - depending on the coil - in German called
automatische SchliesswinkelregelungI wonder if the tiny Guzzi distributor cap would survive the high voltage - maybe one day I'll ask the FIAT-500 club.
- Schoolbook extract (see page 544)
Pages: 13