R75/5 Charging issues

As the title says. Long story short, my rotor was shot so I got the kit from EME, new rotor, stator, stator frame cover with brush holder and brushes, diode board, voltage regulator.

I installed everything, started the bike up and the charge light would not go off (not charging). I checked all my wires, connection, etc. and all seemed good. Battery is newish and charged at 12.8 V. I then went through the component testing as per EME's website, tested the voltage regulator by bridging the two ports (even tried with my old VR), measured the diode board to make sure I only get reads in one direction (passed), resistance between the two rotor rings (also good) and finally the stator. Everything seems fine. I have no idea what I could have done wrong. I also installed new ignition brakers and a new condensor, but the bike is running and that doesn't have any input on the charging (I think).

Probably what I really need now is some detailed instructions on what to measure where with the bike running, e.g. measure A/C output at the stator, DC at the breakers, diode board, something like that. I just don't know enough of this that would let me think this through. If anyone could give me some help here, I would truly appreciate it. I am beyond frustrated at this point, because I can't see anything that could be wrong.......Thanks!

Snowbum has some troubleshooting here for the stock system:

https://bmwmotorcycletech.info/trbleshootALT.htm

I suspect most applies, although he doesn't mention the EME system on the page.

Other than that, unless some members have direct experience with the system (I don't), then calling the EME folks is the next stop.

Just me and YMMV, but my first rule of trouble shooting on an airhead is to throw the battery in the Mississippi River and start with a new battery.

Olaf, I don't know how close you live to the Mississippi. But keep your newly battery for now.

With motor running, what is the voltage across the battery poles? Is it higher with engine running? Maybe all is working but the indicator light is incorrectly lit?

Did you measure the rotors resistance not between the slip rings but between the connectors to the brushes? This is to make sure the brushes are no hung up in the air.

With the motor running use your multimeter set to AC Volts and measure the voltage at all three wires coming off the stator against ground. You should see some AC voltage of about 13V. This should show that the stator coils are connected through.

If the voltages of the stator coils are lot less than ~13V check the current through the rotor. For that take the wire to one of the brushes of and put your multimeter on DC Amps between the disconnected wire and the now open brush connector. It doesn't matter which brush you use - either one works. Start the motor and you should see some 3..4 Amps running through the rotor. Close to 0 Amps indicates there is no input coming from the voltage regulator (VR). Either the wire from the VR is not (correctly) connected or the VR is kaput (unlikely) or not correctly connected.

Oh, something I forgot occasionally on reassemble, the red wire from the starter (on my R100GS) which connects to the diode board.

Can you show us a picture of how your wiring looks now?

/Guenther

Amazingly, all of the threads in the Similar Threads pane below are for charging issues on Airheads...can't be a coincidence!! Might be some good reading there as well.

There was a similar issue here in Fl

I remember a similar issue with an R 75/5 with a new upgraded charging system (not sure of the source) where the charge light wouldn't go out and it wasn't charging. I thing it was boiled done to exposed (not properly insulated from manufacture) in either the armature or stator and it only showed up when to components were installed and motor was running. Contact the Florida Air Marshall on this as he would have the contact info on the Airhead member and maybe even the diagnosis and fix to the problem. It sounds exactly what they encountered at the Winter Rally and long after with an upgrade charging system on a /5.

Great feedback, just what I needed. Thanks y'all! I will tackle this again tomorrow afternoon, and report back. Cheers!

Ok, as promised, I am getting back with some results. Again, I tested components separately before, when they were off the bike and all seems fine. So here you go:

Olaf, I don't know how close you live to the Mississippi. But keep your newly battery for now.
-Yeah it's 500 mls to the Mississippi and I cant throw that far...

With motor running, what is the voltage across the battery poles? Is it higher with engine running? Maybe all is working but the indicator light is incorrectly lit?
-Engine off: 12.95 V, Ignition on: 12.9V, Engine running at 1,000 and 3,000: 12.65 V for both. I had charged the battery over night, it's only about 6 months old and I also "load tested" it, so I am fairly sure the battery is good

Did you measure the rotors resistance not between the slip rings but between the connectors to the brushes? This is to make sure the brushes are no hung up in the air.
-Just did that again, 3.3 Ohm between the rings with a business card slipped under the brushes. But just 1.0 Ohm between the tops of the brushes (business card removed) where they are screwed in. How can that be? Lower resistance with brushes on???

With the motor running use your multimeter set to AC Volts and measure the voltage at all three wires coming off the stator against ground. You should see some AC voltage of about 13V. This should show that the stator coils are connected through.
-Zero voltage here, with Ohmmeter set to AC

If the voltages of the stator coils are lot less than ~13V check the current through the rotor. For that take the wire to one of the brushes of and put your multimeter on DC Amps between the disconnected wire and the now open brush connector. It doesn't matter which brush you use - either one works. Start the motor and you should see some 3..4 Amps running through the rotor. Close to 0 Amps indicates there is no input coming from the voltage regulator (VR). Either the wire from the VR is not (correctly) connected or the VR is kaput (unlikely) or not correctly connected.
- I measure zero Amps. I don't think the VR is kaputt, I used two different ones for testing.

Oh, something I forgot occasionally on reassemble, the red wire from the starter (on my R100GS) which connects to the diode board
-WAIT A MINUTE: My /5 does not have that connection. The diode board connects to the starter relay. Since I basically now have the /6 charging system, do have to add this wire from the diode board to the starter? The wire cam with the set but I though I was supposed to connect everything as it was. Could this be the issue??

I forgot to take a photo, will do later and send that out. Thanks a lot!!

My /5 does not have that connection. The diode board connects to the starter relay.

Click to expand...

Correct! That's what it shows in the electrical diagram for a R75/5 '69 and newer.

How can that be? Lower resistance with brushes on???

Click to expand...

Did you make test with the wire to at least one brush disconnected?

At this point it sounds like rotor is not being energized. To verify that the rotor is OK do the following test.

Disconnect the wire that comes from the voltage regulator and goes to one of the brushes. That should be the brush on the right side looking at the rotor towards the rear of the m/c. Prepare a wire (20 gauge or less would do) and connect it to battery plus and run it all the way to the area of the rotor. Best to have a clip at the loose end. Be careful with the loose end of the wire to not touch the m/c (short!). Start the motor! Attach the end of the wire to the now open brush connector. If the brush and the rotor is OK the rotor should be energized to its maximum and the alternator coils should now produce ~13V AC. If that is true the charging indicator should go off.

Don't let it run like this for too long because the battery will be charged with a bit higher voltage which is not a problem if you do it for less than ~30 seconds.

If this test shows success then the wire from the VR to the brush might be the problem. Check its resistance and correct connection to the VR. If this test fails then either the rotor or the brushes are the problem.

Have fun and be careful not to get a tattoo burn mark from the hot exhaust headers or, create a spark(=short) with the rigged wire.

/Guenther

Perhaps

I have been reading all of the trouble shooting answers and have nothing to add to them.

Perhaps there is another factor involved.

When I installed my higher output charging system, I received a gizmo in a plastic bag along with the other parts. It was marked something along the lines of "Generator light something?" Forgive me, I don't have the part handy and I never used it so I can't remember exactly what it was.

I am rambling, I think it was kind of bypass or add on to the generator light on the instrument cluster. As we all know for the charging system to work, that light bulb must be good and in the circuit.

If you didn't get a detailed installation sheet, I myself would contact EME and have a chat with them.

To be honest, a new system should work. The charging system on an Airhead is not all that complex.

Forgive me for not remembering what the mystery item in the kit was. As I did not need it it is buried in my tool chest now. It was in the kit for a reason, I just don't know why.

Hope my ramblings help. St.

Steven -

I found a /5 kit on the EME website...in looking through the parts, I don't see anything that might appear to be a "bypass" for the charging light:

https://www.euromotoelectrics.com/product-p/edl1-altkit105-2y.htm

It might be one of the smaller wires, but there's not a lot of description on the site. Is this the kind of kit you were thinking about?

Guenther, thanks, I will run that test later today and dammit, no, I did not connect the wires from the brushes when I measured resistance through brushes and rotor (embarrassed smiley)

Steven, I believe what you are refering to is what EME calls "GEN Lamp Energizing Circuit Modification", it did not come in my kit but was listed in the instructions as optional item. It's basically a resistor wire, the EME part# is BOALT ResWire.
https://www.euromotoelectrics.com/searchresults.asp?Search=BOALT+ResWire.&Submit=Submit

Don't know what to call it

Hi, fellas,

Don't know what to call it, gizmo sounds good.

The last two posts catch my drift.

That gizmo (included with my new system but not needed) is the only thing I could think of that is not a direct replacement part for the BMW system parts. If it was not included with the EME kit, it may not be needed.

My electrical schematic memory is not the best. We know the generator warning light must be in the circuit and working in order for the system to work. A diode in the light system allows current flow in one direction and when the system is charging, the current flows in the proper direction and the light goes out. When there is current flowing in the wrong direction as in from the battery and not the charging system, the diode allows current to flow to the generator warning light. The light then comes on. As us Airhead owner's know, if the bulb burns out, the system does not work.

Now, if the GEN light energizing circuit modifier is needed, this could be the solution to the problem. I don't have wiring diagrams here with me in front of the computer. I am only going on poor memory. I would have to see a schematic and a description as to how the modification is made to figure out how it all works.

Again, would not hurt to give EME a call or email. Unless the problem has been solved and if solved, what was the problem and fix? St.

I just had a couple minutes so I went to the garage and measured rotor resistance again with the brushes off (3 ohm) and through the brushes with the wires DISCONNECTED and again measured 1 Ohm!

I then checked resistance between brush holders on both sides against Ground and both sides measure 1 Ohm against Ground! I strongly assume the DF brush holder should NOT have continuity to ground, right? So I am thinking that DF side of the brush holder is not insulated properly from the stator frame. Does that make sense? I will take the stator frame off later to take a look.

Steven, I see where you are going, but I don't know the answer. I also have an email in to EME to discuss latest testing (they were very helpful when I called on Friday and even gave me their cell). I'll report back.

Before measuring very low resistance I first cross the leads to check what the '0' accuracy of the Ohm meter is.

When you measured the DF brush was the wire to the VR still connected? If so your number might be the resistance through the VR to ground and try again with the DF wire off.

I have my suspicion that the DF wire from the VR might be wrongly connected at the VR side. That's why I suggested to test with a wire from the battery to the DF brush. It would show that the brushes and the rotor are OK if the charging light goes off.

/Guenther

Guenther said:

Before measuring very low resistance I first cross the leads to check what the '0' accuracy of the Ohm meter is.
---The zero accuracy is 0.1 Ohm

When you measured the DF brush was the wire to the VR still connected? If so your number might be the resistance through the VR to ground and try again with the DF wire off.
---The DF wire was off when I measured this. And the spade terminal where the wire goes on is insulated towards the stator frame. I measured at my old stator frame and there is no continuity (infinite resistance), so something must be going on there, right?

I have my suspicion that the DF wire from the VR might be wrongly connected at the VR side. That's why I suggested to test with a wire from the battery to the DF brush. It would show that the brushes and the rotor are OK if the charging light goes off.
---I will still do that later when I have time and will report back.

BTW, Guenther is a very German name, isn't it ?

/Guenther

Click to expand...

.

Finally! A note to the vendor would be my first thought after troubleshooting by myself.

New partsq

So, you have all new parts. Things should work. Rarely do new parts fail. The Enduralast kits have been around for awhile.

You can drive yourself crazy measuring things. Why would a person assume a brand new part is defective. Oh yeah, it happens once in a very great while something slips through quality control at the factory and bad parts do get into the market. It is pretty rare.

Concentrate on assembly, Are you sure yo have everything connected properly? concentrate on the wiring diagram and above all, see if the gizmo is needed or not.

If EME gets back to you, they can perhaps tell you what is wrong. Maybe you need the gizmo.

Remember, the light must work, be in the circuit for the system to work. Just because it is on, does not mean it is properly in the circuit. Dang, that does not make much sense. Check the wiring diagram. St.

Wires, Colors, Connections, Observations

Olaf,

Some information and observations.

1. If the rotor windings are shorted out, the GEN bulb will not light. Since your's lights, the rotor windings are not shorted out.

2. It's easy to tell if the alternator is charging. Use a Volt meter and attach it to the battery terminals. With the engine off, you should see on the order of 12.6 volts if the battery is fully charged. Start the bike and rev to 3500 RPM. You should now see about 14.3 volts at the battery. If you don't the charging circuit is not working.

3. To test the voltage regulator, disconnect the three prong plug from the bottom. Use a paper clip and stick it into the (D+) terminal (BLUE) wire of the connector and the (DF) terminal (BLUE-Black) wire of the connector. With your voltmeter connected to the battery, start the bike and slowly rev the engine. If the battery voltage rises, then the voltage regulator is not working.
--> CAUTION: Do NOT rev the engine too much as the voltage can go above 14.3 volts and damage your battery. You are verifying if no voltage rise in test #1 with the voltage regulator in the circuit is solved when you remove the voltage regulator from the circuit.

4. The GEN light lights when there is no DC current flow from the (D+) terminal of the diode board (that's the terminal on the back side of the diode board with a BLUE wire(s) attached to it.) On the /5 bikes there are (2) blue wires on that terminal.

5. The path of the BLUE wire from the GEN bulb to the voltage regulator and then to the brushes is the ground path for the GEN bulb. That path goes as follows:
- TO (D+) terminal on the STARTER RELAY via a BLUE wire
- FROM (D+) terminal on the STARTER RELAY to the (D+) Terminal on the back of the diode board via 2nd BLUE wire
- FROM (D+) terminal on the back of the diode board to the (D+) terminal on the voltage regulator via BLUE wire
- INSIDE voltage regulator, (D+) terminal goes to (DF) terminal (BLUE-Black) wire.
- FROM (DF) terminal on voltage regulator to (DF) brush terminal on alternator stator cover
- FROM (DF) brush terminal on stator cover, through the rotor coil to the (D-) brush terminal on the stator cover, which is the ground.
Since this entire path acts as the ground path for the GEN bulb, and your GEN bulb stays lit, this path is working.

6. If you mistakenly put the BLUE-Black wire from the voltage regulator on the (D-) brush terminal on the stator cover, the alternator will not work. The brush terminals, (D+) and (DF), are cast into the stator cover next to the terminals.

7. The (DF) terminal (the right brush terminal IIRC) has several insulators; a sleeve around the bolt and two insulating washers. If they are cracked or missing, the alternator will not work.

8. If you installed new brushes, and you soldered them, you may have a "cold" solder joint. (not overly likely)

9. The springs on top of the brushes can hang up, or not be inserted on top of a brush preventing a brush from fully contacting the rotor slip ring.

10. The pigtail on the brush can be too short preventing the brush from fully contacting the slip ring (not likely if you installed new brushes, but can happen if you pushed too much of the pig tail through the hole before soldering it, or the pigtail is crimped so it restricts the brush from moving fully to the end of it's path).

11. There is GEN bulb bypass resistance wire you can buy. It protects you should the GEN bulb filament burn out. It has no bearing on your problem.

12. I documented how the charging system works with wiring diagrams:
--> Charging Circuit
It maybe of some help as you work on this problem.


I hope this helps.

Best.
Brook Reams.

I measured at my old stator frame and there is no continuity (infinite resistance), so something must be going on there, right?

Click to expand...

Very likely! I never had a R75/5 so I don't know how this connection is isolated against ground. Maybe some plastic washer is missing here?

I think Brook is the right person to help you there.

Excellent list of things to check Brook!

/Guenther