Topic: No Charge Problem

[gunr]

OK electrical gurus,  my 77 750K drained the battery yesterday. Luckily I only had to push her a thousand feet but I was huffing and puffing.

I tested voltage across the battery terminals (with a new battery) and got no increase in voltage with rpm increase.
Mark's book says to jump across the white and black terminals on the regulator, after disconnecting the green wire, to actuate maximum voltage from the stator to confirm it's ok.

Before I do that I replaced the regulator with another I had and I do get a slight increase in voltage across the terminals now.  The voltage increased to 12.4 at 4000 rpm but I didn't hold it there long.

Family picnic this afternoon then I'm back at it.
TIA for any advice.

[PeWe]

Make sure to fully charge battery before measure how charging works on bike.

CB750 shop manual ch 8 describe how to service regulator if needed.

I had recently issues with not good enough charging.
12v to regulator OK, I cleaned ign switch harness connector under tank anyway.


Check all connectors to be clean and fully seated.

Inside front sprocket cover, 3 yellow, 1 green, 1 white.

Measure conductivity of the yellow alternator wires, 0.4ohm between 2 yellow since that is 2 coils of 0.2ohm each.

Field coil white-green 7.2ohm.
All these easy to measure when open the white connector behind carbs.

Clean them all, contact spray.

Connectors on regulator and wiring to/from rectifier.

Regulator can be serviced inside.
Core gap and point gap.
The voltage adj screw should not change by itself.

Green wire to ground at seat lock must have good contact to frame and minus on battery.

I grinded to shiny metal and covered with alu paste.

It charge really well now. 14.5V not much after 3000rpm when fully charged.
No drop when turning on headlight, ev 0.1V sometimes.

I have a voltmeter between my gauges so I can see constantly when riding.

City riding with brake light and blinkers use take some riding time to recover to max voltage again.

[bryanj]

Most common problem is bad connections, occasionally regulator but very rarely field or stator coils UNLESS mechanically/physically damaged

[gunr]

Well Thanks Gents!
Got to dive into the problem today and started with a fully charged AGM battery.
Gently pulling out the wires connecting all the components, cleaning as I go. Got back to the stator connector and one yellow wire seems to far back out of the connector...Yep! The little leg on the spade that keeps it in the plastic wasn't in far enough!
Now it's charging.
Thanks again Guys.