Post
by cadman » Fri Apr 19, 2013 6:13 pm
Aternators output AC voltage which is converted by a rectifier to DC volts and regulated by a regulator to stop overcharging the battery. The Dream has an alternator and it does output AC volts but since there is no regulator they routed 2/3 of the alternator output to the rectifier and then on to the battery. If you ran this way with the headlight on the battery would not charge, so they took the remaining 1/3 of the alternator output and tied it into the rectifier when the headlight was on.
Test your alternator by disconnecting the brown and yellow wires at the plug by the rectifier. Start the motor and check the AC voltage between these two wires from the alternator. I get about 13/15 VAC at idle and it goes up as engine speed is increased. At about 3000RRPM I can see 50VAC.
This should be good VAC for battery charging but I only get a maximum of about 12.5VDC at the battery with the engine running. (This is because we are only see 2/3 of the alternator potential). Next I ran a wire from the Pink wire in the headlight housing which is the third leg of alternator output, (headlight off) back to the rectifier. Measuring between the yellow wire and the jumper wire I get he same AC voltage as between the yellow and brown wire. Next I connected the jumper wire to the terminal on the rectifier with the yellow wire. I now have the full potential of the alternator available. I can now get about a 1/2 volt increase at idle and over 13VDC at the battery with the engine running about 2500RPM.
So your choice is run stock with marginal charging or run with a jumper from the pink wire and get full charging voltage and run the risk of overcharging the battery. I have a few early Honda 750 charging system components. I will wire these in to see if I can get full charging voltage and regulation.
