charging system help

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stangracr

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Im pretty new here but have done lots of reading on here including curlys charging system test. I performed the test and found the regulator bad. I purchased the regulator/rectifier combo from mikes xs. I installed this and still no charging. Not sure what to look for next. After finding the charging system inop I installed the new brushes and brush holder that I had from mikes . Still no charging. Any ideas.




ed
 
Sorry to repeat but stop throwing parts and go back to trouble shooting. Most every part of the charging system can be tested, most can be bypassed to to prove or disprove operation. This applies to the regulator, I think it's in the Curly's guide Some have their eyes glaze over when electrical is mentioned. The charging system is fairly simple, careful measuring with a VOM repeated until you are sure of your measurements will reveal where the problem is. On sytems of this age any part could be the problem including bad conectors or broken wires. The best advice I can offer is test test test. If you are unluckier than most you could have more than one problem that can add to the fun. Do not forget the fuse box can appear good but not be passing current. Best of luck to you.

I've got to say; I am lazy AND I have parts bins, the EASIEST way to figure out a charging system IS to sub in known good parts till the problem disappears.

Mustang racer; what year is your engine?
 
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http://xs650temp.proboards.com/index.cgi?board=Charging&action=display&thread=3461&page=1

Here's a reprint.

This is taken from one of Curly's posts, and is one of the best troubleshooting guides we have seen:

1. First charge your battery to at least 12.5-12.7V.

2. Find a really thin feeler gauge like 0.010" or 0.015" and hold it pointed down about a half inch away from your generator cover on the engine. Now turn the key on. If your regulator and rotor are working the feeler gauge should slap the case when the magnetic field is created in the rotor. If nothing happens or the magnetic effect seems really weak then go on to the next test.

3. On the solid state regulator models all you need to do is locate the green wire at the regulator plug and make a jump from it to ground. That bypasses the regulator and allows full battery current to flow through the brushes out of the rotor through the green wire to ground. That causes the rotor to make a stronger magnetic field which in turn causes more current to flow in the stator. If your battery terminal charge voltage jumps up to 14.5VDC when you rev the engine then the regulator or the ground connection for the regulator is your problem.

4. If nothing changes then it's time to check the voltage on the brown wire (It may be black on your bike) at the positive brush with the key on. It should be very close to battery voltage. The brown wire that feeds the brush gets its power from the brown wire at the keyswitch. Check the voltage at the three wire keyswitch connector while it's plugged in by probing from the backside of the connector with the key on. Again you should see the same voltage as the battery. If you do get full battery voltage there then repair the brown wire circuit between the switch and the positive brush. If not then the switch is either bad or the red wire from the battery is not passing the full current like it should. If that's the case then keep going back along the red wire, through the main fuse until you find the source of the voltage drop. No more than 0.3 VDC drop is acceptable.

5. Once you have full voltage to the positive brush re-check the charging voltage to see if you're getting 14.5 VDC or better at the battery when revved to about 3,000 rpm. If you still don't have a charge then do the feeler gauge test again. If it slaps the case your rotor and regulator are working and you can go on to stator checks. If not then pull the brushes out of their holder and use an ohm meter to test the rotor. Measure the rotor first by touching the tester leads to the brass slip rings. Then take one lead and touch anywhere on the engine that's not painted. For the first test you should see between 5 and 5.5 ohms between the slip rings. On the second test between one slip ring and the engine you should see infinity on the meter. Any reading lower than 5 ohms on the first test or less than infinity on the second test means you have a bad rotor. Replace it. If it tests good then go on to the stator checks.

6. At the stator wire connector locate the three white wires. Use a voltmeter set on the AC scale to test the three possible connections between the white wires by probing from the backside of the connector. (The connector should be plugged togeter for this test) With the engine running at idle you should see about 10.5 to 11 AC volts (Not DC) on each of the three combinations of white to white that you make. If you get a very low reading on one or two legs then something is grounding your stator. If you have high readings on any of the legs (i.e. 16-18VDC) then your rectifier is bad.

7. If you got low readings on any of the stator voltage checks then unplug the connector and use your ohm meter to check the stator windings. Check the resistance between the three fabric covered wires (stator side) on the side of the connector. On each white to white connection you should read about 0.4 to 0.5 Ohms. If you get a very low reading on all of the three combinations find the single Yellow wire connector and disconnect it. Re-check your stator resistance. If the readings are now good then the yellow wire or safety relay are shorted. If there is one or more that still read low after disconnecting the yellow then check those legs by touching one lead to ground with the other on the white wire. You should see a very high Kilo ohm or infinite reading. If you get a low resistance check the stator lead pigtail to see if it is pinched by the cases or rubbed through on the frame. If that looks ok then your stator is shorted and needs to be replaced.

And that's about it except to say that dirty connections and worn brushes account for most of the charging system problems. Good Luck you'll find the problem.
 
The bike is a 1975. I wasn't just throwing parts at the bike. I tested everything using the guide on here. The wires from my rectifier were melted so I thought it would be a good idea to upgrade to the rectifier/regulator combo. The burnt wiring only went about 10" into the loom. I think I have more then one concern. Checked out the rotor lastnight and from slip ring to slip ring I have an open circuit. Guess I will get one ordered and get the tool. Is it cheaper to have it rewound? One other thing that Im not sure about is when checking the stator at the plug I have 3 ohms of resistance when checking all the white wires. If I check the white wires to ground I get a reading (dont remember what the resistance reading was right now) If I unplug the yellow wire or unplug the safety relay then that concern goes away. I dont mind working on the bike or spending some money. I just want to get everything I need and get it done at one sitting. Thanks for all the help. I know there is tons of info on charging systems on here. I have read lots of it.


I have 2 fox body mustangs 1991 GT 347 and a 1992 LX 331


ed


ed
 
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I believe unplugged is correct on the stator the yellow wire does ground through the relay coil so would create a circuit to ground. Melted wires and the open circuit on the rotor would have me looking for a short somewhere......... the wire bundle from the rotor and stator under the LH cover has lots of potential problem areas. On the rotor when you have it pulled look for a broken connection, there are two visible connections where the coil wires attach to the slip rings. I have seen at least one broken connection but had no luck resoldering it.

Oh there are also two different mikes regulators early vs late charging systems the early regulates +12 brush the late regulate the ground side brush. A backwards hook up (which has been done many times) smokes the regulator instantly.
 
I purchases the early one and followed the directions. Im in hopes everything is okay with the regulator. The melted wires were from a earlier short near the rectifier. Im hoping the rotor replacement will fix the charging system.







ed
 
On the rotor I don't have personal experience since I have "back up parts" but the custom rewinder in Atlanta?? seems to be a better choice than new ones found at a "popular" XS supplier. They loan the tool also.

Quote: "If I was to replace the rotor, a rewind is better than Mike's new rotors and about $100 less. Call Gary at Custom Rewinds, 1-800-798-7282. $125 last time I checked.
Leo"
 
Thanks. I just gave them a call and left a message. Would like to get this taken care of pretty soon.




ed
 
Thanks for Curly's list.

I will charge the battery and give it a go, not very electrically experienced.

You can upgrade to an electric ignition i.e. Pamco, and can do Hugh's PMA mod, what is the chrysler reg/rec mod? Do all these go together? I believe you can't do PMA without a new ignition.

Just trying to research alternate parts, options etc so I know which direction to head when I find the problem assuming it is more than a loose connection.
 
Whacked the battery on the charger..step 1 anyway. Sorry but I'm a bit too green to follow the instructions :( in Curly's troubleshooting guides,



2. Generator cover on the engine. Is this the small Yamaha logo on the Left Hand side?

3. On the solid state regulator models all you need to do is locate the green wire at the regulator plug and make a jump from it to ground. Which models are soild state? Mine is a 74. Also what does make a jump from it to ground mean?


I'll ask more questions i'm sure once I try these..
 
AussieHard said:
2. Generator cover on the engine. Is this the small Yamaha logo on the Left Hand side?

Yes.


3. On the solid state regulator models all you need to do is locate the green wire at the regulator plug and make a jump from it to ground. Which models are soild state? Mine is a 74. Also what does make a jump from it to ground mean?


You did not have a solid state regulator stock.
On your bike you will use a wire to put (jump) +12 volts from the battery to the outer brush, that should make the alternator go to full charge. If it does the problem is in the wiring or regulator if it doesn't charge then the problem is stator, rotor, or wiring.

I'll ask more questions I'm sure once I try these..
Click to expand...
See answers above.
While researching this answer I pulled a stator frame out of the parts box to verify I told you the correct brush. It "looked good" I used a continuity tester to check the green and black wires, the black had no continuity. I removed electrical tape from the wiring bundle and found 5!!! crimp type connectors under the tape. A wire had fallen out of one of them. Want to bet this bike had been abandoned because of charging issues? TRUST NOTHING THE PO has done.
 
I have a 75 and Im having problems as well. I have a new rotor and coil and no charging. I have followed all wires and getting no voltage to brush and no slap at the case. Can anyone help?
 
Got the bike out today……….Dry weather today to be working in the street on my bike. Charged the Batt again…..The battery was fully charged 13.3V Just for referance

Lost the damn terminal nut so had to make a new one, how annoying, simple jobs are never simple!

Bike kicked started on first go after using primer kick method. Again test for reference.
Hope fully this will help until I get my battery issues sorted……


Last time after taking the bike for a ride with a few stop starts the bike gets harder and harder to start until it is dead! (Using elec start)..

Not sure if it is a charging issue, or the elec start is just draining the shit outta the battery.

Did the feeler guage test today and it slaps the tank when turn the ignition switch. Not sure what to look at from here.

In Curlys test it says if it fails move to step 3. What if it passes? Does that mean the issue is someplace else? Or should I still follow on the steps?

I don't have a soild state re stock on my bike thanks Gary!
I have 2x Bosch coils so they have been upgraded, and I picked up one of Hughs PMA second hand unused, (not fitted)…..

I am at the point I would pay someone $100 to come around and sort this out with me…..Don't want to pay a shop cos that way I won't learn!!!
 
Reread Curly's test….. I jump to Step 6 - Stator Checks. Not sure I know how to follow this one….

Where do I find the white wires to test???
Anyone done a utube video or have some photos to go with Curl's test???
 
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Lets start with a few basics. From 70-79 they used a seperate mechanical regulator and a Selenium rectifier. In 80 they changed to the solid state combined reg/rec.
In the 70-79 the stator brushes are wired with a green and a black wire. The black wire hooks onto the upper left brush screw and is connected to the inner brush with a metal strip. The green wire hooks to the lower left screw and hook directly to the brush.
On the 80 up the green wire hooks the same. It has a brown wire that hooks to the upper right brush screw and hooks directly to the brush.
On the 70-79 models the regulator is before the brushes and turns the power on/off to the rotor on the green wire. The black wire grounds the brush to complete the circuit.
On the 80 up thr reg is after the brushes, power is sent to the brushes on the brown wire, the green sends the power to the regulator where it grounds the circuit.
Now to bypass the regulator as in step 3 on the 80 up you do as in the step. On the early 70-79 you need to run a jumper wire, a 10 amp fuse inline won't hurt, from battery positive to the green wire on the brushes.
The regulator bypass will make the alternator put out the max power it can. Have your voltmeter hooked up to the battery as you do this, as the voltage can climb to 15 to 20 volts. If you let it go that high you may cook other parts.
On the step 6 stator check if you follow the wire bundle up from the stator you will find a blue wire from the top of the tranny come in, a bit farther and you will find where the yellow wire comes out and the rest go into a large connector. At this large connector is where you do the checks. Just probe into the connector to touch the white wires.
To do the ohm checks unplug the large plug and the single yellow wire.
The yellow wire is the centrel connection of the three white wires. As the alternaor starts to make electricity some is sent out on the yellow wire to trip the safety relay. The safety relay stops the starter from running, on the later models it also turns on the headlight. With the yellow wire hooked up when you check the ohms from a white wire to ground you will get a 20 ohms reading instead of infinity. The coil in the safety relay is 20 ohms.
Leo
 
I got someone a little more experienced with bikes to give me hand today and we ran through Curly's list. Thanks for the tips XSLeo.

Step 1. Charged her up and rode over, wasn't a fun trip she was running like a pig.
Step 2. Got Slapped
Step 3. Did anyway..
Step 4. Did anyway
Step 5. 5.66 ohms Between slip rings just over range (negligible) Passes test 1&2.
Step 6. 11.5-11.8 AC Volts Within range



Stator Bush @ Idle 11.2-11.7 ohms, drops when revving engine.
Battery @ High RPM 13.2V
Lights on @ idle Drop - 0.2-0.4

Summary the system seems to be functioning……..however there is a bit of a loss through the system. So maybe the amount of short runs, stoping & Starting the bike is not getting a chance to charge up???

Sanded the battery connectors, to get a little more conductivity. Thinking maybe a PMA will help & more kick less starter motor.

Warren also adjusted the idle speed up so she behaved like a lady and rode beautifully home, no farting or stalling. Which was a good thing since it was the first time I have ridden in the rain and at night.
 
Aussie, which bike is this on? You list a 74 a 78 and an 80. On the 74 and 78 the mechanical regulator can be adjusted to up the charge voltage.
On the 80 it can't be adjusted.
In your post you list Stator Bush @Idle 11.2-11.7 ohms, dropped when revving engine I think you meant brush and volts not ohms.
If this is correct then the voltage drop between the battery and brush is too much. With your battery reading 13.3 volts the volts at the brush should be no lower than 12.9-13 volts.
I would check all the connections between the battery and brush to find the voltage drop. Most probably in the key switch, the contacts get dirty. Some switches are screwed together, some crimped. If you can get it apart you can clean the contacts, bright and shiny are a good thing. A bit of dialectric grease will help keep them clean.
Clean, tighten and grease all the wiring connections.
Leo
 

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