RD250 Charging Issue

[1976RD400C]

After you get it back together, hold a small lightweight screwdriver right near the bolt that holds the rotor on, turn the key on and off and you should feel the magnetic pull as the rotor is energized, to prove the regulator is powering it up and the rotor is ok.

[BlueR32]

Didn't you also have a challenge with the phenolic washers?  Perhaps you have a ground one one of the terminals?

Some progress here! I didn't mess with the brushes but I joined the green and black wire terminals directly together. You can see in the pic the green wire is frayed and may well have been shorting against the brush holder.

So I started the bike and now seeing some different behavior:

• With key on, screwdriver is pulled toward the rotor bolt
• Neutral light brightens up when revved
• If I unplug the red wire from the rectifier to battery the revs go up a little
• Plug red wire back in, revs drop (alternator loaded up?)
• Multi-meter still jumping around when bike running but after revving it up a few times the battery showing 13.2 volts after switching off motor.
• Battery drops to steady 12.5 volts after a minute or so

I think I'm back in business but I'd be grateful for comments on the findings above. Also many thanks to all who chimed in on this, it's been extremely helpful. It also helped me focus on the simple things so I didn't just rush out and buy a complete HPI system (I was having some wallet anxiety over that)

[m in sc]

yup. think ypu got it. I'd probably just strip the green wire back and use a connector to join the 2. I'd still get new brushes those are just worn out