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Coil Testing

Posted: Wed Aug 06, 2014 8:57 am
by Hugh
As an experiment as electrics is something of a mystery to me and to see if OK been testing my coils. Now a puzzle. They are stamped Lucas but not sure what voltage as a Boyer ignition was fitted. This apparently requires 2 6V but I have no part number I can see on coils to reference back. The resistance ohm readings are for primary on both coils 4.2 and on the HT lead side 5.22 and 5.39. I am having trouble finding what the manufacturing readings should be. But do these figures suggest they are 12V. Can anyone confirm or suggest how to check voltage and do these readings mean both coils are OK? Any advice appreciated and thanks. Hugh

Coil Testing

Posted: Wed Aug 06, 2014 11:29 am
by Mark M
It would help if you told us what bike this is and when (if you know,) the Boyer system was fitted. Information on the Boyer site says, "Actual resistance will vary with condition of ohm meter's battery. Also your coils resistance will vary with manufacturer and age." and then lists various coils by manufacturer and resistance. Your figures are not the same as any quoted but are nearest to Lucas 17M12 12v coils. REgards, Mark

Coil Testing

Posted: Wed Aug 06, 2014 2:51 pm
by Nettshubby
If Boyer recommends 2 6 volt coils, that would be because they fire both together, i.e. a "wasted spark" on exhaust stroke on opposite cylinder to one firing. Firing 2 x 6 volt together is equal to firing one 12 volt on a single.