Commando charging issue.

Hi all and I know this has probably been asked many times before! I have just bought a 74 Commando 850 and already own a 72 Commando. The 850 charging light stays on all the time BUT there is a charge coming from the alternator leads as I connected a multi meter direct to them were they come out of the chaincase but there is no charge going into the battery. Any suggestions would be greatly accepted! Can it be the rectifier under the seat? Or could it be the warning light assimilator that is between the coils I think. The bike has electronci ignition. Help!!

Peter Waller said:

The 850 charging light stays on all the time BUT there is a charge coming from the alternator leads as I connected a multi meter direct to them were they come out of the chaincase

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Did you do the same test at the rectifier (green/yellow & white/green)?

Peter Waller said:

Can it be the rectifier under the seat?

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Yes, it could be.

Peter Waller said:

Or could it be the warning light assimilator that is between the coils I think.

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Yes, or the Zener diode. The test procedure for the rectifier and Zener:
Sections J4 & J5.


Or could be the 2MC emergency starting capacitor so try disconnecting the earth/ground (red) 2MC connection.

Or could be a bad warning light assimilator. If you have a multimeter run the engine with a meter in the battery terminals. If you’re getting more than 13 volts when you rev the engine then the charging system is fine.