Thanks for all the help everyone! I spent some more time testing this morning. Going over everything. Here it is in question and answer format so I don't get lost (and other people may benefit from it later on). This duscussion is primarily going on over in my
CB400F Charging Issue thread but again, I've posted it here to keep this project area thread up to date.
Unplug both the alternator and the rectifier from the bike's wiring harness. Also disconnect the green wire from the regulator. Using your multimeter, check the resistance between the green
wire in each of those couplers, on the harness side of the coupler, to chassis ground. Do the same for the regulator's green wire. There should be close to zero resistance - like less than 1/2 ohm.The green wire on the harness side of the rectifier to ground tested 1.5, the regulator green wire tested 1.7. Is this bad? Here's a photo so you can verify that I have the tester on the correct setting,
Plug the alternator back in, and reconnect the green wire at the regulator. Make sure the battery has a good charge. You're going to check stator output on the three yellow wires at the harness side of the rectifier coupler. Set your meter to read AC volts. Start the engine, and let it idle while you attach one probe of your meter to ground, and the other to one of the three yellow leads. Watch the meter as you rev the engine to at least 4,000 rpm. Then repeat on the other two yellow wires. What was the maximum AC voltage you saw displayed?Maximums:
1: 20
2: 21.4
3: 21.7
Next test would be to disconnect the white and black wires from the regulator, jumper them together, and repeat the test. This will "full field" the alternator and force it to put out it's maximum when you rev the motor to around 4,000 rpm.Maximums:
1: 19
2: 19
3: 19
60VAC if you tested between pairs of yellow wires rather than yellow to ground.I did get up around 60 on all three.
Questions - With the key on, is the voltage on the black wire = battery voltage?Black wire= 11.5 volts
Battery = 11.5 volts
Are you certain the blue jumper wire is making good contact with both wires?Yep, I am.
Did you test resistance between each yellow wire and ground? There should be no continuity. The meter should read the same as if the probes weren't touching any wires.Yes, it just read 1, which is what it says when nothing is connected to it.
Now for the rectifier. I followed the SOHC/4 FAQ guide (checklist shown below) in both the resistance and continuity settings as I wasn't sure which was correct.
Here is the results on the resistance setting:Note the 1. I will refer to this as ERROR so as not to confuse myself.
VI. Check the five leads on the rectifier.
A. To perform a forward bias test first connect the red tester lead to the green ground lead.
B. With the black tester lead test all three yellow wires.
C. Resistance must fall between 5 and 40 ohms. This showed ERROR, like nothing was connected to the tester for all three wires. See above photo to verify I have the tester set correctly.
D. To perform a reverse bias test connect the black tester lead to the green ground lead.
E. With the red tester lead test all three yellow wire.
F. Resistance must be greater than 2000 ohms. Same as above, ERROR for all three.
G. Connect the black tester wire to the red and white rectifier lead.
H. With the red test lead test all three yellow wires.
I. All three must have between 5 and 40 ohms.I got 2.4 on the left terminal then ERROR on the middle and right terminals.
J. Connect the red test wire to the red and white rectifier lead.
K. Test all three yellow wires with the black tester lead.
L. Resistance must be greater than 2000 ohms. I got 3.5 on the left terminal then ERROR on the middle and right terminals.
Here is the results on the continuity setting:VI. Check the five leads on the rectifier.
A. To perform a forward bias test first connect the red tester lead to the green ground lead.
B. With the black tester lead test all three yellow wires.
C. Resistance must fall between 5 and 40 ohms. Left terminal: .530
Middle terminal: .578
Right terminal: .543
D. To perform a reverse bias test connect the black tester lead to the green ground lead.
E. With the red tester lead test all three yellow wire.
F. Resistance must be greater than 2000 ohms. ERROR for all three.
G. Connect the black tester wire to the red and white rectifier lead.
H. With the red test lead test all three yellow wires.
I. All three must have between 5 and 40 ohms.Left terminal: .001
Middle terminal: .551
Right terminal: .565
J. Connect the red test wire to the red and white rectifier lead.
K. Test all three yellow wires with the black tester lead.
L. Resistance must be greater than 2000 ohms. Left terminal: .001
Middle terminal: ERROR
Right terminal: ERROR
Now for TwoTired's suggestions:
You DO want to know what voltage appears on the Black wire to the Vreg and how it relates to the actual battery voltage. Make two tests; at the battery terminals and the black and green at the Vreg and subtract one for the other.Key in off position:
Voltage at battery terminals: 12
Voltage at black and green on harness side side at regulator: 0
Subtract one from the other: 0
Key in on position:
Voltage at battery terminals: 11.5
Voltage at black and green on harness side side at regulator: 11.5
Subtract one from the other: 0
Alternately, place one voltmeter probe on Battery POS and the other on the Black Vreg terminal. Then, place one voltmeter probe on the battery NEG terminal and the other on the Vreg Green terminal. Add these two readings.
Battery POS and on black at harness side side at regulator: 12.1 (with key in the on position, 11.9)
Battery NEG and on green at harness side side at regulator: 0 (with key in the on position, 0)
You mentioned you have a Dyna -S ignition. Do you also have 3 ohm coils? Can you measure the primary resistance of the coils?I do have a Dyna S ignition but I got the 5ohm coils as I had heard the 3ohms might be a problem on my charging system. My headlight is off unless I turn it on as per the Australian model spec (I believe the US model was always on). I would like to measure the measure the primary resistance of the coils. How do I do that?
Maybe you should tell us more detail about ALL the electrical mods you've made to the bike?There's the two relays, the lighting in the mini gauges, the CB350F right hand switch and the Dyna ignition with 5ohm coils. Nothing else has been touched and is as stock.
Thanks again for persevering through this for me. I owe you all a beer if this bike runs!
Rick.