Topic: Not Charging CB550K [Problem Solved!] [Problem Broken Again!]

[campbmic]

I will take her for a long ride tomorrow and we shall see what happens

[bamabiker]

There is a very helpful book "Motorcycle Electrical Systems Troubleshooting and Repair" by Tracy Martin .  Its written in clear terms and has practical examples of using your mm and other test devices to unravel the electrical mysteries of our old bikes.  Amazon sells it or your local library might have a copy.  I'm sure there are other books which are as good or better but its the one I'm familiar with.
If you're using the book and you hit a snag, its a lot easier to describe what you were doing and what you need help on.  Good luck.

[Laminar]

I have a good working regulator and rectifier from a '76 550 for sale if it turns out you need one or the other.

[campbmic]

Installing the new rectifier didn't solve the problem. However, I got another great 2 hour work out pushing the bike back home. What would be the next step?

[campbmic]

Well I disconnected end of the red/white wire (which goes from the rectifier into the battery) on the battery side. I left the other end connected to the rectifier. I tested the red/white wire and got the following;

At 1k RPM its at 3 DC Volts
At 4K RPM its at 4.5 DC Volts

How many volts does the bike use to run? Should there be more voltage in the wire or not?

Heres a picture of the wire I'm talking about with a red arrow pointing to it.

[scottly]

Should be closer to 14V minimum. Before, you when you removed the headlight fuse, you got no voltage at the regulator. Do you indeed have 3 fuses? There should be a main, a taillight, and a headlight fuse. Has the wiring been altered?

[campbmic]

I don't believe the wiring has been altered. When I put the bike back together I had to deal with the rats nest in the headlight but no wires looked as if they had been tampered with. Also, wouldn't this mean that the issue is in my alternator not producing enough power?

[scottly]

The reason I asked is that the reg should be powered off the main fuse (the higher amp rating of the three), not the headlight fuse.

[scottly]

Try to identify which fuse is the the headlight fuse and pull it out, then measure the voltage at the regulator field terminal, like you did before. (from the artsy diagram, it appears to be the center one)

[campbmic]

I got sick of using the analog MM so I went and bought a digital one. The headlight and bike both run off of the main fuse. I'm guessing I might have done that when I was in the rat's nest in the headlight.

So your saying disconnect the power to the regulator and see if the alternator is producing any AC power?

[scottly]

No, if you disconnect power to the reg, it will not work. I'm just wondering why the headlight is not off when you pull the headlight fuse. Also, if the headlight isn't on, it won't be sucking 5 amps out of your battery while you are trying to fix things.

[scottly]

Anyway, with everything in the charging system hooked up like normal, check the batt V, and V at the ign and field terminals at the reg, Ign on, engine off. Then start the bike, and measure the same points with the motor at 4K rpm, and report back. (still bugs me about the headlight...)

[campbmic]

I took the headlight out  And put in the newly charged battery from autozone

Bike ON but NOT RUNNING
Battery = 12.0V
Ignition (Black Wire) = 10.9 V
Yellow Wire Running To Alternator = 10.9V

Bike ON AND RUNNING at 4K RPM
Battery = 11.8V
Ignition (Black Wire) = 11 V
Yellow Wire Running To Alternator = 11 V

So what does this tell us? And what would be the next step?

[scottly]

Well, it tells us that there is a 1.1 V drop thru the wiring to the reg, the battery voltage actually decreases with the motor running, while the voltage to the reg increases(the drop decreases) by .1 V. Also, the max available V is being sent to the field, which should make the alt output max. Hmmm With your new meter, sent to the lowest ohm scale, touch the leads together; this represents a dead short, or as close as your meter can measure one. Note that figure, and subtract it from your low resistance reading. (give me actual numbers you measure, the offset only once) Disconnect the field at the plug closest to the alt, and measure the ohms across the field coil.

[campbmic]

Sorry, I don't completely understand your terminology, remember I'm a noobie when it comes to electronics. Use the wiring diagram that I posted if you can it helps a lot.


When you say, "Turn your meter to the lowest ohms scale and touch the two leads together" what do you mean by two leads? Also bike on or off or running?


What is a low resistance reading?



I understand the field is part of the alternator but I'm not completely for sure how to do this, "Disconnect the field at the plug closest to the alt, and measure the ohms across the field coil."




Thanks again for all of your help!

[scottly]

BTW, if you need help using your meter, send me a clear pic or scan from the instruction manual of the front and I can talk you through it...
HA! for once I checked a new reply before hitting post! 

[campbmic]

I can use the meter to measure resistance, volts, ohms etc.
I just don't know what you mean by;

"Turn your meter to the lowest ohms scale and touch the two leads together" what do you mean by two leads? Also bike on or off or running?


Note that figure, and subtract it from your low resistance reading.
What is a low resistance reading?


"Disconnect the field at the plug closest to the alt, and measure the ohms across the field coil." I understand the field is part of the alternator but I'm not completely for sure how to do this,

[scottly]

I meant your meter leads.

A low resistance resistance reading is, say less than 1 ohm, typical of coils of wire used in alternators and starters. Resistance=ohms

All resistance tests are done WITH NO POWER APPLIED!

The alternator is mounted at the left end of the crank shaft (at least on 750s, I don't know if 550's are different). The wires for both the stator (the three yellow wires that end up at the rectifier) and the field (1,that ends up at the reg, ) come out from the left side cover, and there should be plugs in between where you can unplug and isolate the the field and stator.
The field should have 2 wires. (at least if it's like a 750) I would like you to measure the resistance across these two field wires, disconnected from the rest of the harness.

[Spanner 1]

Please unplug the alternator plug under the battery and test the field coil and the stator coil thus;... ( the plug has 3x yellow a white and a green wire ). Now, turn your digital meter to its lowest OHM scale ( but NOT the diode setting )..... connect one test lead to any yellow wire and the other test lead to any other yellow it must read 0.2 ohms ( up to 0.5 ohms is acceptable ) Repeat for the other yellow wires. Then test the field coil, one lead on white ( does not matter which lead to what wire on any of these tests ) and one lead on green, reading must be between 5 and 7 ohms. You will find one of the coils are bad....I bet its the stator.. IMO.

[campbmic]

Alright test complete!

-When I touched the two multimeter leads together I got a 0.9 OHMS reading

-When I tested all three different combinations of yellow wires I got a 1.1-1.5 OHMS reading
My manual says it should be .35 +- 10%

-When I tested the Green wire and White wire coming from the alternator I got a 5.3 OHMS reading
My manual says it should be 4.9 +- 10%

By the way I have a real wiring diagram in the back of my manual. I kept trying to figure out how to do these test thanks to both of you for walking me through it in simple terms! So these tests mean that its good correct? What would be the next step?

[scottly]

It means they passed that test! Next, check the resistance from any one stator wire and either field wire to ground. It should read open (the same as with both meter leads Not touching)
Wait a minute, you mean 1 combination of the stator was, 1.5, and the other 2 were 1.1??

[campbmic]

The lowest OHMS setting I have is 200 so its very difficult to make the reading stop jumping. It was reading around that range depending on where I put probe on. I just found an easier way to standardize all of the tests and they all came out within range so they should be good.

I did the next test;
-Connecting the MM leads together I got 0.6 ( Each time I turn it back on I think it might change)
-Connecting the ground with Green or White wire reads open
-Connecting any of the yellow wires with the ground reads 0.7 (which is 0.1 resistance)

By the way what does this test? The manual doesn't show anything about this.

[scottly]

The test to ground checks for a break-down of insulation, ie short, and the resistance checks verify the coils aren't open, like one of the wires inside had broken. The absolute values aren't so important as that they match each other, especially with the stator, because these low values can't be easily measured with a mm. (that's why I had you check your meter by holding the leads together: your meter thinks 0 ohms is from .6 to .9)   

[campbmic]

So does this mean the stator and field are working properly?

I just did another test with my new rectifier. Basically I have one of these;
http://www.radioshack.com/product/index.jsp?productId=2062584

It has two terminals for AC power, one terminal for a DC outlet, and one terminal for a ground. I attached it up to the bike and ran at 3k with the three yellow wires not connected to the rectifier so I could test the ends of them. The three wires had the following AC levels

#1 12V
#2 10 V
#3 8V

The voltage went up and down because my idle isn't perfect but these are about the numbers. Should the rectifier transform 100% of the AC into DC power? Hypothetically would the DC outlet be at 30V if I hooked the three yellows up to the rectifier?

Whats the next test I should run?

[scottly]

Wrong type of rectifier!!!! This is used to convert single phase AC to DC. Our systems are three phase. Single phase has 2 wires in, 2 wires wires out, 3 phase has 3 wires in, 2 out. Just how in the hell did you hook this up???