[Not Charging] Alternator.. or something else

[Fire-medic]

I’ve read they could be a problem.. About the meter see the last picture. I tried multiple volt settings to check if I would get response.

The pickup coil could be a problem, but not this problem.

It appears your readings are on the ohms setting, 0.5 and 0.7 ohms. On the third attachment, it looks like you're measuring DC voltage at the battery, but why is it O? Where is the red(+) lead grounded-to, the battery + terminal?

"...a lot of backfire... ." But it's running? Do you know that the right front ignition coil powers the left-front spark plug/cylinder, and the left front ignition coil powers the right-front spark plug-cylinder? Hooking-up the wire harness improperly to the ignition coils, or the ignition coils to the wrong spark plugs will cause constant backfiring.

Also, let's make sure that we are using the correct terminology:

A 1990 has one pickup coil for the ignition source signal. That wire comes from the left front engine cover, and it's two wires.

The high-tension ignition coils power the spark plugs, there is an ignition coil for each spark plug, two are behind the steering head, and two ignition coils are under the seat, on-top of the battery compartment.

 

[glennvanlaerhoven]

Your correct about the coils, these are connected correctly.

About the measurements, yes im checking dc voltage. in the document to diagnose the problem the mention to check the stator, connect 1 lead of the meter to 1 kabel of the stator(white cables) and 1 to the ground or negative of battery both read 0

 

[02GF74]

I'm gonna throw my tuppence in without reading in detail what you are measuring.

The stator winding are part of the alternator that produces electricity when engine is running.
The first test is to check for continuity in the windings ie that there is not a broken wire. These are the low ohm readings = good.

Then I'm not sure what are the voltage readings you are taking. Note taking resistance (ohm) readings with the battery connected are meaningless. (the meter itself has a battery and it applies a voltage to measure a current to calculate the resistance, having a second battery is gonna mess this up)


When the engine is running, you would expect a voltage reading at the stator, beat I'm mind this is AC so would read 0 if the meter is on DC range.

Once I've looked at the manual ill post back to ensure I've not posted duff information.

 

[glennvanlaerhoven]

When the engine is running, you would expect a voltage reading at the stator, beat I'm mind this is AC so would read 0 if the meter is on DC range.

this what i try todo but i keep getting 0.. 1 plug of the multimeter in the cables.. 1 on the negative from the batterie or the frame

 

[02GF74]

Apologies if you have done this but let's start at beginning.
Step 1.
Check stator wiring.
Disconnect battery. Disconnect the plug from alternatior. Measure resistance between each pair of white wires leading to the alternator at the plug.

See diagram below with spoke pointing to the plug connecting the white wires.

Each should be about 0.4 ohm. (in other words pretty damn low)

Then next step is to check resistance between each one of the white wires going to the alternator and ground eg chassis or negative battery terminal. So one probe to one of the white wires and other to ground. There should be no continuity so all 3 readings show infinite resistance).

If the above checks out, alternator is fine and we move to the rectifier unit.

 

[glennvanlaerhoven]

oke thanks for taking your time , i really appreciate it but thats whats ive done

the white cables give 7ohm and 2x 5 ohmz.

if I measure the voltage over the cables.. with negative... i got zero, i’ve attached the pictures in my previous post.

thanks again for clearing this out.

 

[02GF74]

No problem, I kinds thought you'd done that but the readings you report are 10x what the Haynes manual. Either the manual has error or your multimeter is out. I'm not sure that is a problem but the important thing is that there is continuity.

And you meased there is no continuity between each white wire and ground?

Next step is regulator. There are 6 doides to convert AC to DC.


!!!!!! Ignore this, FM had already posted this.
With the plug and battery disconnected measure each diode in both directions.

Meter to resistance range.
Red lead on pin 1 black on pin 4. This should give low resistance.
As above but red probe on pin 2. Low r.
As above red probe on pin 3. Low

If all resistance reading are low, diodes are working.

That is diodes 1-3 tested in forward direction

Red probe on pin 5, black probe on pin 1.
As above, black probe on pin 2
As above, black probe on pin 3.

If all readings are low, then doides 4-6 are working in forward direction.

Red probe on pin 4 and black probe on pin 1, then 2.then 3.

If resistance is infinite, diodes 1-3 are working in reverse direction.

Finally black probe to pin 5, red in turn to pin 1, 2 and finally 3.

Again resistance should be infinite.

You ll have to turn your head sideways asfor some reason the phois being rotated.

 

[02GF74]

Right. I've looked at your fitst wo photos and in the first I think I can see a decimal point. So the reading is 00.7 which is pretty much bang on.
A light reflection obscures the decimal pont so that would be 00.5 ohm.

Is that a decimal point in the green circle?

 

[02GF74]

oke thanks for taking your time , i really appreciate it but thats whats ive done

the white cables give 7ohm and 2x 5 ohms.

I think I see a decimal point so you are seeing 0.7 and 0.5 ohm.

if I measure the voltage over the cables.. with negative... i got zero, i’ve attached the pictures in my previous post.

thanks again for clearing this out.

3rd photo. I don't know what you are measuring here. Is the plug connected, is battery connected, is engine running, where does the black and red probes go?

 

[glennvanlaerhoven]

your totally right its 0.7 and 0.5

3rd photo red pointer to white cable black pointer to negative or frame. both give 0 when engine running.

 

[02GF74]

Yes but is the RR plugged in?

And when you say white wire, there should be 3 of them (but all should act the same). I can see you have selected correctly AC volts.

If there is fault in the RR it may be taking alternator voltage down, so see test below.

The alternator can be tested by disconnecting the RR and measuring voltage between any 2 white wires with the meter set to AC voltage.

Re. For this test you need to set your multimeter to an (AC) alternating current voltage of a minimum of 100v AC depending on how far you test, the lowest setting on my meter is 200v AC which is more than enough. With the bike running and connector block disconnected measure the AC voltage between each of the three Stator connector terminal pins as in the previous resistance test as per the diagram above and make a note of what they read. You will have around 20v AC or thereabouts at 1000rpm depending on the amperage of the bikes charging system

From here:
https://www.aberdeenbikers.co.uk/motorcycle-charging-system-diagnosis-checks/

 

[glennvanlaerhoven]

I measured with the RR disconnected. Yes i mean the 3 white wires. i will check tomorrow. What i get between them when the engine is running, but i tought ive already done that and got 0v aswell!

 

[02GF74]

Hmmmm.....

There should be a voltage on all 3 white wires differing only by phase.

So putting the meter (AC) range across any 2 of them should show a voltage.

The alternator is not grounded (see earlier post with circuit diagram and tests) so your test connecting one probe to battery negative lead or chassis is not valid, hence why meter shows 0v.

Think of the alternator, when engine is running, as a fancy 3 terminal battery. Connecting your meter across any 2 terminals should show a voltage.
Connecting one terminal to the meter and another to some other point (battery negative lead or chassis or kitchen cooker) will show zero as the circuit is incomplete. This is no different to putting one probe on say the positive end of an AA battery and the other onto the metal of your cooker in your kitchen (or motocyucle chassis) - the meter will show zero as there is no connection between the other end of the battery and the cooker.

I would suggest measuring across any of the 2 white wires with RR disconnected as per the article I referenced.... and I predict that Sean's prediction is validated.

 

[MaxMidnight]

I’ve read they could be a problem.. About the meter see the last picture. I tried multiple volt settings to check if I would get response.

Yes, but if it is a charging issue that you have(?) why are you bothering with the p/u coil?

As has been pointed out above, if you are trying to read the output from the alternator then you should set the meter to read AC volts; from what I can see from the pictures this.

It would appear that you have continuity through the stator coil and assuming that the rotor magnets are OK then you MUST get an output.

 

[02GF74]

Yes Max, that's exactly what I'm saying - but I have not seen result of continuity from stator to ground tests (should be none = infinite resistance).

 

[glennvanlaerhoven]

oke another step closer! It looks like the stator is generating power! between 50-80v, when i rev up to 5000rpm. So this means that the RR is done?

I can buy MOSFET RR (with fins) with 20% discount for 70 euros. So I Think thats the way to go?

 

[02GF74]

yes - and you've test all 3 two white wire combinations?

If you can be bothered, you can check out the diodes as per test posted by me and FM to confirm deadness of the RR but a replacement on eBay (ignoring the ones from China) vary from £ 22 to £ 80 (M&P reputable company that probably is selling the same Chinese made regulators).

 

[glennvanlaerhoven]

Yes measured over all 3 of them!

I got 1 year warranty and its a dutch company, next day delivery. So i probally go for that! I will check the RR before ordering one. Will let you know what it will give me.

 

[glennvanlaerhoven]

No problem, I kinds thought you'd done that but the readings you report are 10x what the Haynes manual. Either the manual has error or your multimeter is out. I'm not sure that is a problem but the important thing is that there is continuity.

And you meased there is no continuity between each white wire and ground?

Next step is regulator. There are 6 doides to convert AC to DC.


!!!!!! Ignore this, FM had already posted this.
With the plug and battery disconnected measure each diode in both directions.

Meter to resistance range.
Red lead on pin 1 black on pin 4. This should give low resistance.
As above but red probe on pin 2. Low r.
As above red probe on pin 3. Low

If all resistance reading are low, diodes are working.

That is diodes 1-3 tested in forward direction

Red probe on pin 5, black probe on pin 1.
As above, black probe on pin 2
As above, black probe on pin 3.

If all readings are low, then doides 4-6 are working in forward direction.

Red probe on pin 4 and black probe on pin 1, then 2.then 3.

If resistance is infinite, diodes 1-3 are working in reverse direction.

Finally black probe to pin 5, red in turn to pin 1, 2 and finally 3.

Again resistance should be infinite.

You ll have to turn your head sideways asfor some reason the phois being rotated.

View attachment 76165

oke i now did this test all diodes give 540 except 1 is giving me 520..
All the reverse have no continuity.. Oke now im in doubt again.. is this rectifier still good?

So What should be the outcome of the R/R towards de battery 14.4 right? If i measure the outcome of the R/R red cable and Ground i measure 0.8v (im i checking this right?) which is in my opinion way to low? after running for like 1,5minutes the RR is bloody warm.. (i guess its normal because it need to take 50v back to 14.4 v?)

I think im getting closer by the measurement

 

[davidon]

Yes, but if it is a charging issue that you have(?) why are you bothering with the p/u coil?

As has been pointed out above, if you are trying to read the output from the alternator then you should set the meter to read AC volts; from what I can see from the pictures this.

It would appear that you have continuity through the stator coil and assuming that the rotor magnets are OK then you MUST get an output.

Off topic but just found out that Gomez Addams (John Astin) is still a professor at John Hopkins Univ here in MD at 91!