What is the battery voltage with key and everything off and engine not running?

I would go through the non charging procedures in the Yamaha service manual.

11.84v


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Maybe wire(s) are loose under the ignition switch? Did you take a look when you had the switch off?

Your battery is low or possibly bad. Should be at 12.6 or so fully charged with no load. I'd charge the battery (external charger) and try again. You need to use a motorcycle rated charger... like 1 amp max.

System relies on battery voltage to energize magnets to charge... so if battery is bad or low, it affects the available charging. Since voltage is up when revved, if you rode it long enough with engine revved the voltage would probably slowly come up.

The old generators don't have a lot of extra power above what it takes to keep bike running so recharging a low battery can take the generator a while. And it's hard on the generator. Best to always start with charged battery on that model.

Or battery could be going bad... again, hard on generator and it will never charge up. Leaving key on that long would have really drained the battery. And you're lucky ignition coil didn't actually melt and die. Or points burn up. I've seen both happen.

My charger is a three amp, I’ll get a motorcycle battery charger.

Thanks Mark.

Coil will survive & obviously has. But charging isn't happening so why not. Is the starter working as that & charging rely on brushes being under tension & the 4 usually wear at a similar rate. Hard to know where to start except brushes first, & they'll work--until they don't--which normally means the spring have run into the brush guide & brushes are past the limit mark. If you had the regulator lid off it'll be clear to see the cut out arm pull itself in if charging is happening--well its not happening at the mo. Also when happening you can feel the motor work a bit harder between a slow idle just above stopping, & say 2000rpm.

All 4 of the brush springs were like this. Am I correct in assuming that the spring should be centered on the back of the brush sitting in the notch in the back side of the brush?

The back side of the brushes are all about .030” proud of the brush guide.

Edit:

Clearly the springs were moved out of the way so the brushes didn’t interfere with reassembly, then were forgotten. The springs are back in place. The starter still does not work.

I ordered 2 pairs of brushes from eBay:

Yep sits as you say. Probably someone's set them like that with brushes pulled right backt to make it easy to remove & refit--especially refit the assembly so as not to damage--likely break off--the brushes. Shell charge & have starter--will travel lol--after this. I hope.
Bugger, i should have read ya whole post. So no starter, any clicking from solenoid. Any charging when you kick start it.

I’m gonna get a low amperage charger today, get the charge up in the battery, and see if the bike maintains the charge on its own.

There was a clicking noise when I hit the starter button for a while, but it no longer clicks.


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