1977 cb400f not charging.

[Rydog400f]

So I have a brand new harness and regulator/ rectifier and agm battery. The battery is holding @ 12.5v while running. I ride it a bit getting around 6,000rpm and the lights dim, bike stutters and dies. I checked resistance at the alternator plug. field coils resistance is ~ 7ohms between the green and white wires, and the stator coils yellow wire average ~ 1.1ohms. This exceeds the factory recommended specs. I'm also running a new dyna coil ignition if that helps. Any ideas? Thanks! Another thing. If i put around the neighborhood below 4,000rpm and check the voltage it reads `12.5 at the battery. When I take it up to ~45mph and get up to 6,000 the battery drains and the exhaust and breather hose start to smoke, and the battery reads ~9.5v..

 

[Sonreir]

Start by reading AC voltage between the yellow wires while the bike is running. You should get about 30VAC at idle and an increasing value as revs increase.

 

[Rydog400f]

Start by reading AC voltage between the yellow wires while the bike is running. You should get about 30VAC at idle and an increasing value as revs increase.

Checked, not even producing 1 v.

 

[Sonreir]

OK... and green and white wires going to the alternator...

Any voltage on those when the bike is turned on and running?

 

[Rydog400f]

OK... and green and white wires going to the alternator...

Any voltage on those when the bike is turned on and running?

Same, still not producing a full V.

 

[Sonreir]

Double check the wires coming from the harness plug to the alternator plug.

The colors should all match up in the same slots.

 

[Rydog400f]

Double check the wires coming from the harness plug to the alternator plug.

The colors should all match up in the same slots.

They do, the oil and neutral lights work.

 

[Sonreir]

OK.

Lets check the regulator next.

It should have three wires: Green, black, and white.

Green terminal should have continuity to ground and black wire should have 12V when the ignition switch is on.

 

[Rydog400f]

OK.

Lets check the regulator next.

It should have three wires: Green, black, and white.

Green terminal should have continuity to ground and black wire should have 12V when the ignition switch is on.

Green is good, black shows 13v.

 

[Sonreir]

Good enough.

Any voltage on white?

 

[Rydog400f]

Good enough.

Any voltage on white?

No, 0.00 with ignition on/off.

 

[Sonreir]

OK... one last thing to check...

The green wire coming back from the alternator... Do you have continuity to ground?

Also, when unplugged, you should NOT have continuity to ground on the white or green wires coming from the alternator.

 

[Rydog400f]

OK... one last thing to check...

The green wire coming back from the alternator... Do you have continuity to ground?

Also, when unplugged, you should NOT have continuity to ground on the white or green wires coming from the alternator.

Yes.

 

[Sonreir]

Sounds like a bad regulator, to me.

You can bypass the regulator by connecting the black wire from the regulator to the white wire from the regulator.

Next, verify the exciter is properly working by removing the alternator and seeing if a wrench will stick to it now that power is flowing through the circuit.

 

[Rydog400f]

Sounds like a bad regulator, to me.

You can bypass the regulator by connecting the black wire from the regulator to the white wire from the regulator.

Next, verify the exciter is properly working by removing the alternator and seeing if a wrench will stick to it now that power is flowing through the circuit.

I've got a brand new one from you guys.

 

[Sonreir]

I've got another I can send. Can you please send the existing one back to us so I can check it out?

Please email your address to me at info@sparckmoto.com

 

[Rydog400f]

I've got another I can send. Can you please send the existing one back to us so I can check it out?

Please email your address to me at info@sparckmoto.com

Done.