pin-pointing charging woes

[ExecutivePowerNap]

Hey-o

So I'm ready to push this bike off a cliff...One day I suddenly had charging issues with the bike. I used a multimeter and observed approx 12 volts and slowly, steadily falling while running = not charging. Opened the alternator/generator up and sure enough one brush was below specs, replaced it and still no help. Wiring appears to be OK, oldish but OK. I even used a liberal amount of spray electrical cleaner. Didn't help.

Is the stator coil the last thing it could be? I'm really at my wits end with this thing. Is there any more prodding I can do with the multimeter?

Thanks in advance.

[Airhead]

Hi, did you ever look at the useful infoHere?

[JimR]

Hey-o

So I'm ready to push this bike off a cliff...One day I suddenly had charging issues with the bike. I used a multimeter and observed approx 12 volts and slowly, steadily falling while running = not charging. Opened the alternator/generator up and sure enough one brush was below specs, replaced it and still no help. Wiring appears to be OK, oldish but OK. I even used a liberal amount of spray electrical cleaner. Didn't help.

Is the stator coil the last thing it could be? I'm really at my wits end with this thing. Is there any more prodding I can do with the multimeter?

Thanks in advance.

Hi,

A good old air cooled FZ I guess ! did you clean the slip rings on the genny ? if not take it off again & clean them.

(Slip ring = the track that the brush runs on).

First off charge the battery fully

Then do the battery voltage test 14.5~14.8 @ 4k, if you dont get this do the following :-

check all connections to the rectifier/reg i.e 3 whites, red and black, these should be well clean .. no green anywhere and the copper connectors need to look copper colour rather than black/copper. If that's ok go to stage 2

The 3 whites from the genny will output 50ish volts AC (across each white to white so there are a few combinations).

if no voltage check the 3 whites from the genny for burns (brown patches) and breaks.

do that for now if its not fixed I'll add stage 3

Regards Jim

[ExecutivePowerNap]

Wow! Thanks for that info! That diagnosis chart was exactly what I've been looking for.

As far as Mr Jim R wonders: I'll be cleaning up those 'slips' they're not bad though. Generally, connectors look good the 8 socket connector to/from the rectifier is kinda iffy, but no green to speak of since I used the contact cleaner 3 days ago. Where would I go/get to redo a lot of the wiring without going broke at the dealership? (connectors, harnesses) I'd like to wire it myself just not sure where to find parts without highway robbery prices = I be broke!

I'm a little confused about testing reistance though. Do you unplug the connector for the 3 white genny wires and take the multimeter probes and basically jump them (red to plug '1' and black to where it would've plugged in?). Never did much electrical troubleshooting in the past, so this is all kinda new.

Tip o' the Hat,

Guenther

[JimR]

Wow! Thanks for that info! That diagnosis chart was exactly what I've been looking for.

As far as Mr Jim R wonders: I'll be cleaning up those 'slips' they're not bad though. Generally, connectors look good the 8 socket connector to/from the rectifier is kinda iffy, but no green to speak of since I used the contact cleaner 3 days ago. Where would I go/get to redo a lot of the wiring without going broke at the dealership? (connectors, harnesses) I'd like to wire it myself just not sure where to find parts without highway robbery prices = I be broke!

I'm a little confused about testing reistance though. Do you unplug the connector for the 3 white genny wires and take the multimeter probes and basically jump them (red to plug '1' and black to where it would've plugged in?). Never did much electrical troubleshooting in the past, so this is all kinda new.

Tip o' the Hat,

Guenther

well you have 3 checks to do. From your reply the slip rings & brushes are ok, but I would think a bike of this age would be correct. If the 8 socket connector 3 whites, red,black, brown & green oh missed one perhaps its not used

do the red to all whites & reverse (with an ohm meter) then again with the black instead of the red.

Regards Mr Jim R

[ExecutivePowerNap]

"do the red to all whites & reverse (with an ohm meter) then again with the black instead of the red."

Sorry if we're beating a dead horse...I've tried all different combos still not quite sure of what you mean

Am I leaving the connector plugged in and inserting the red probe to where the (white) wire disappears into the connector? Or am I disconnecting it? ug......

I also keep reading about unplugging the stator connector to check resistance - only way I've gotten anything is by jamming one end in the 'wire' side and the other lead to the female (opposite side) on said connector.

Seriously, I'm not a 4th grader pardon the lack of comprehension...

[Neil Brown]

Hi,

With Jim's help, I have just fixed the same problem on my 1987 FZ600!

Here's a bit more info for you...

Firstly disconnect the 8 way connector. This is the regulator / rectifier connections.

On the wiring loom side of the connector (ie not the regulator side) you should have the following wires:

Red - goes straight to the battery + ve

Black - goes straight to the battery -ve

Green & brown - goes to the brushes on the alternator

3 whites - goes to the stator coil in the alternator

1 empty space

Ok, heres what to do to confirm that the alternator & wiring is OK.

Take a multimeter, set it on the resistance range (Rx1). Start by shorting the meter's black & red test leads together. you should get a reading of near to zero, mine read 0.6 ohms. Make a note of that reading, because it is the resistance of the test probe leads.

Now go back to the wiring loom side of the connector & choose two out of the 3 white wires (doesn't matter which two, we will test all possible combinations!) touch your test meter probes on those connections- you might need to press hard to get a good connection if they are corroded, or dirty. You should see approx 1 ohm between each combination of pairs of white wires. Your meter might read more than this. Mine read 1.6 ohm, so then subtract the value that you measured earlier to compensate for the resistance of the meter probes. If any of the pairs measure much more than 1 Ohm, there is probably a problem with the stator or white wires.

Now measure the resistance between the green and brown wires, that should be around 4 Ohms (taking into account probe resistance).

If either of these two measurements are far out, you might need to check the joins in the cable loom. remove the right hand seat panel & under there you will see connectors joining the 3 white & brown & green wires. Disconnect these & measure the side that goes down to teh alternator. you should get slmilar values to to those I mentioned above.

If these all seem Ok, switch you meter onto DC voltage range and measure between the red and black wires on the 8 way connector (loom side) you should get the same voltage here as you get directtly across the battery terminals.

Next, set your meter to the Diode range, and taking the regulator side of the 8 way connector we will measure the 6 regulator diodes. Start with your probes on one of the white leads & the red one, you should get either a reading of about 0.5 or open circuit, now swap the red & black probes over, you should get the other one of the two readings above (this is because the diodes in the regulator only conduct electric current in one direction. Now do the same with the other 2 white wires to Red (should measure the same for each one)

Then measure the 3 whites to black. You should again find the same readinbg for each white / black combination.

Have a go at all this, then poost back your findings & we'll take the next step.

Good luck.

Neil

[JimR]

Hi,

With Jim's help, I have just fixed the same problem on my 1987 FZ600!

Here's a bit more info for you...

Firstly disconnect the 8 way connector. This is the regulator / rectifier connections.

On the wiring loom side of the connector (ie not the regulator side) you should have the following wires:

Red - goes straight to the battery + ve

Black - goes straight to the battery -ve

Green & brown - goes to the brushes on the alternator

3 whites - goes to the stator coil in the alternator

1 empty space

Ok, heres what to do to confirm that the alternator & wiring is OK.

Take a multimeter, set it on the resistance range (Rx1). Start by shorting the meter's black & red test leads together. you should get a reading of near to zero, mine read 0.6 ohms. Make a note of that reading, because it is the resistance of the test probe leads.

Now go back to the wiring loom side of the connector & choose two out of the 3 white wires (doesn't matter which two, we will test all possible combinations!) touch your test meter probes on those connections- you might need to press hard to get a good connection if they are corroded, or dirty. You should see approx 1 ohm between each combination of pairs of white wires. Your meter might read more than this. Mine read 1.6 ohm, so then subtract the value that you measured earlier to compensate for the resistance of the meter probes. If any of the pairs measure much more than 1 Ohm, there is probably a problem with the stator or white wires.

Now measure the resistance between the green and brown wires, that should be around 4 Ohms (taking into account probe resistance).

If either of these two measurements are far out, you might need to check the joins in the cable loom. remove the right hand seat panel & under there you will see connectors joining the 3 white & brown & green wires. Disconnect these & measure the side that goes down to teh alternator. you should get slmilar values to to those I mentioned above.

If these all seem Ok, switch you meter onto DC voltage range and measure between the red and black wires on the 8 way connector (loom side) you should get the same voltage here as you get directtly across the battery terminals.

Next, set your meter to the Diode range, and taking the regulator side of the 8 way connector we will measure the 6 regulator diodes. Start with your probes on one of the white leads & the red one, you should get either a reading of about 0.5 or open circuit, now swap the red & black probes over, you should get the other one of the two readings above (this is because the diodes in the regulator only conduct electric current in one direction. Now do the same with the other 2 white wires to Red (should measure the same for each one)

Then measure the 3 whites to black. You should again find the same readinbg for each white / black combination.

Have a go at all this, then poost back your findings & we'll take the next step.

Good luck.

Neil

Thats pretty much it in a nutshell so that may fix the problem !! do we need to goto stage 2 !!!

Regards Jim

[ExecutivePowerNap]

Alright now we're cooking!

The correction factor is .3 ohms, so all numbers are with correction applied

Stator is OK - (manual calls for .5 to .6) .5ohms all around, same at connector loom

At 8 point connector black, red, and all whites are all showing appropriate numbers/voltages/etc

Resistance reading from green/brown (brushes) at connector was .1/.2 .

Then checked for continuity (i.e. no breaks, right?) and OK. Beep. Beep. Green wire at plug (the 2 prong plug on right side, not the 8) to the green wire brush itself, vice versa for brown. Keep in mind, one brush was just replaced. Both are the correct length >10mm.

Field coil resistance should be 2.7 to 3.3 ohms. Is that what I should be getting from the brushes?

Only problem I had was: getting a reading from the rotor itself. I checked both slips (recently cleaned up with steel wool) and got .2?!? How is that possible when touching the probes to each other results in .3? Wondering if the rotor is at fault?

Made some progress (THANK YOU SO MUCH!) not really sure if we found the problem though....

[ExecutivePowerNap]

Soooo....how am I to figure out what's next? Further checking the rotor? Brushes? Kind of at a standstill til you give me a little more work to do...

[Airhead]

Soooo....how am I to figure out what's next? Further checking the rotor? Brushes? Kind of at a standstill til you give me a little more work to do...

Hi are you sure its a charging issue? Does your battery go flat if left for a period of time, indicating a leakage issue?

Another thing i noticed when reading this is that Neil stated the field coil resistance to be 4.0 ohms, but you have stated it as

"Resistance reading from green/brown (brushes) at connector was .1/.2 . "

... Which would indicate either a short circuit there, Or you didnt put a slip of paper between the brushes and slip ring and had the connector block plugged in. Or that i have mis-understood what you are saying here, because this should be the field coil resistance figure you quoted as

"Field coil resistance should be 2.7 to 3.3 ohms. Is that what I should be getting from the brushes?"

Also did you do any testing to ground (chassis) from all coil connections field and stator, switch meter to maximum resistance reading, black lead to the steel body and red lead to coil connections, expect no reading, any reading is an insulation breakdown.

Next, your voltage regulator is a moving contact (relay) type yes?

Remove the cover and check the contact have not stuck and are free to move also clean the contacts with a petrol soaked rag, or if they look burned use a strip of fine emery or medium wet / dry to clean them, Although they can get so burned they are un useable and a replacement would be needed in extreme cases.