Charging problem

[tri650]

On my 78 XS11 I keep losing my battery as it is not charging. I get about 80 miles before it is dead.

I tried the rev test and the voltmeter did not move. I put in a new stator/coil from a donor bike as well as a voltage regulator. Still can't get the charge to change as I rev the motor. Checked all connections - I think I got all of the important ones. What am I missing?

[DGXSER]

The biggest ones to check are the ones behind the fuse panel, between it and the battery box.

[bikerphil]

As a test, you can try tapping into the dark green field coil wire and connect to ground. Check again with a volt meter at the battery and see if it is charging. Make sure the ground connection at the regulator is solid and the ones mentioned above are clean first though.

[old_chopper]

Just fought this same battle. Make sure you have 12vdc with the key on at the brown wire going to the stator/field coil. If so check the right side case to see if there is any magnestism from the fields. A thin feeler gage works great for this. If yes and yes start the bike and unplug the connector with 3 or 4 wires coming out of the stator. Check across any two of the same color to see if you have 10-30 vac. If so then the stator is working and the regulator is suspect.
Hope this helps.

[Incubus]

Does your tach work?

Patrick

[tri650]

No - tach does not work. And that started when I started having charging problems.

[Incubus]

That points to the vreg.

[tri650]

I took the one off of the donor bike and replaced the old one - of course that assumes the donor bike vreg was good. How do I test this?

[Incubus]

Put it on, start the bike and measure the voltage across the battery. If, when you start it up, the tach starts working - that's a good sign. But you still have to measure the voltage. I've had a vreg go bad and overcharge rather than undercharge.

Patrick

[tri650]

Thanks - I will check that out tonight. I recall the tach was not working at all - even from the start. It was working previously before I had the electrical problems.

Also, since I went through all of this I lost my neutral light and turn signal lights - any relationship to everything else going on?

[Incubus]

No, those are unrelated systems. The turn signals will light and not flash if the bike isn't charging and the battery is low, but if they aren't lighting at all then I'd check the fuse. The neutral light is just one wire. It runs from the switch in the bottom of the case. When the bike is in neutral the circuit is complete (the switch on the case completes the ground). When the bike is in gear the circuit is not complete. Should be pretty easy to trace.

Patrick