3YF charging

[dan3]

Hi, my 3yf has a charging issue. When it's idling it will charge at 12.40v, but when the headlight is on it drops to around 11.78. At 3k rpm it reaches over 14v but with the headlight on it barely makes 12v. Surely the voltage is meant to be higher?
Do you think it's the stator not putting out enough voltage, a bad earth, bad reg/rec or dodgy headlight?
Thanks!

[donnybach]

Even idling you should be charging at around 14 volts. Make sure the battery is 100% charges and good,test it for cranking amps, clean everything up and test your stator. Popping another reg rec on may do it instantly.

[motorang]

I the reg/rec has bad earth the voltage will be too high.
Check if the headlight is the problem ... connect a spare headlighgt bulb directly to the battery and see what the voltage does.
If the drop is the same, your issue is most likely a bad battery.
Reason may be the reg/rec or a bad stator or some other possible reasons, the cheapest one being a fuse (box) problem.

Stator can be tested hillbilly style by disconnecting the regulator and wiring three spare headlight bulbs in between the three white wires, which will pull 3x 55 = 165W. If that gets BRIGHT the stator is OK.
Revving too much will blow the bulbs though, so would check voltage while trying as well.

Pictures ... https://www.xt-foren.de/xt-phpbb/viewto ... 7&t=150809

Andy

[dan3]

Well I finally got a chance to have a proper look today.
When I took the stator connector apart to test the output I twisted it slightly and the ignition clicked off (engine not running!). Twisted it back and the ignition clicked back on. Every time I moved or squeezed the connector it was breaking the circuit. So I popped the pins out, cleaned and checked them and reassembled. No more clicking and getting much better voltage now. I've got a spare loom somewhere so I'll swap the connector over at some point for a permanent fix.

[donnybach]

Good news. Cheap fix.