Charging issue, stator regulator rectifier

[Xslille]

Hi everybody,

I'm a French dude, and pretty new in mechanic or electrical. I hope my English will be understandable.
I have a xs400 4g5 1980 se. The bike was running good but few days ago it stopped at a red light. After waiting few minutes I achieved starting the bike again and riding 10km, but then the same thing happened few times. So I checked the battery voltage and it was pretty low with the engine off, 11v. It didn't go higher at 2000rpm.
I've read few topics on xs400 and it seems that it might come from the stator or the regulator-rectifier.
First I checked the stator's resistance, between the three white cable. My meter first showed a 1.5 ohm value for few seconds then going down to 0.8. The value was constantly slightly moving.
I also checked the regulator and the resistance between the green and brown cable was 15.7 ohm.
The rectifier resistance value between different cables were 9 - 13 - 5 - 0 ohms. The values were constant between the three cables.
Finally I charged the batterie to 12v, started the bike and the meter showed 11v at 2000 rpm.

I would like to know if those result says I should change my wiring Armature or the RR box. I have checked the connection between the cables, and it seems to have no corrosion nor anything.

Ps: I've used this document View attachment 4349

Thank you!

 

[Scorpio1963]

Im not familiar with this part of the bike yet but I`ll ask and question then others with more experience can chime in.
How old is your battery,is it possible that its getting weak and not holding a charge?

 

[Xslille]

The Battery is quite new (4-6 months).

Thanks for answering

 

[Scorpio1963]

I know there are threads on the forum about this issue it seems to be rather common problem on these vintage bikes.Like I mentioned I have not had to mess with my stator or charging system but from what I read on here you are right track by testing the ohms and resistance.Unfortunately I don't know what those numbers mean.A more experienced member should chime in and help.Maybe in the mean time use the search function on the site and see if you can come up with some threads that will help.

 

[Xslille]

I already checké the other threads and they were a big help. My issue here is I'm not understanding properly the result I get.
Anyone has some idea were my problem might come from, by reading those values?

Thanks

 

[Scorpio1963]

I know for fact there are people here than can help,I have read about this issue before with people running the same test that you have,they have given the results of their testing.I don't know if its because the site is having growing pains but sometimes I feel you have yank teeth just to get answer to your question.
Try this page
http://www.xs400.com/forum/search.php?searchid=320807
I will ask members of this forum that have experience with the nature of fellas problems to please chime in and help him.You experienced members that arnet partiicpating are doing your best to scare off the new people that need help.This site is here to share knowledge so I pleed for those that do to do so.Scorpio

 

[vim420]

Hey welcome to the forum! So i just typed out a huge response and accidentally deleted it haha. So apologies, this was done in a rush.
First off if you need to ride it everyday, and keep getting stuck. I found that unplugging unnecessary lights will help start her up again. I usually start with license plate light, gauge cluster and headlight(if the battery is really dead). For a while i had no tail lights either just to make it to work, even with charging battery every night.

Next! It is normal for resistance reading to drop like that, the correct value is when it stops, in you're case 0.8. Cant recall off the top of my head what the values for the regulator test are supposed to be, but alot of info can be found using the manual found at this thread http://www.xs400.com/forum/showthread.php?t=4503. I suggest going through chapter 6 and doing at least number 3 and 4.

Also, a fully charged battery should read 12.7. and upwards of 13.5 while revving.
Good luck! I just gave up on mine after months. First time ever taking something to a shop for more than mounting tires.

 

[Xslille]

I feel by reading to the documents that my stator and rectifier are fine, the regulator seems
To be the issue since it only shows 15.7 ohms and should be 140 ohms.
My question is; Will a bad regulator normally show those symptoms ( battery not charging, engine shut off at red light and starting back after the engine (the régulator??) gets colder?

 

[vim420]

From my experience, if you have a bad regulator but a working stator it will usually result in over changing . The stator produce electricity and the regulator caps it (14.5v on these bikes I believe). I would have the same thing happen where it would stall at a red light. If you hold the brakes on at a red light and you feel it big down, try release brake ( if its safe) to draw less power. I also had that where it would "recover" some power after sitting. I don't believe that is a symptom of a bad regulator but more so just a characteristic of our batteries. I noticed that if I have a fully charged 12.v battery and drainit down to say 11.5v it will recover some charge. You can watch it happen with a multimeter.

 

[XSLeo]

Fully charge the battery, build a jumper wire with alligator clips on both ends. With your meter hooked to the battery, start the bike. Set the idle speed screw up so it idles around 2000 rpms. Hook the jumper to a good ground. Now touch the other end to the green wire at the reg. You might need a unbent paper clip to reach inside the plug to get to the wire. This bypasses the reg and your alternator should put out it's max power this should make the battery voltage rise up.
On testing the reg/rec the way to test the rec half is to test for ohms on the wires. Hook the red lead from the ohm meter to thered lead of the reg/rec. Touch the black meter lead to the three white wires. Write down the readings. Now hook the black meter lead to the vred reg/rec wire, Touch the red lead to the white wires. Write down the readings. The exact readings are not as important as if the readings one way is at least 10 times the other reading.
This tests 3 of the 6 diodes in the rec half of the reg/rec.
Now repeat the tests you just did but use the black reg/re c wire. This will test the other 3 diodes.
There isn't really any test for the reg half.
All this should be in you repair manual.
One the stator, test the three white wires as thee sets of two, as in 1-2, 2-3, 1-3. The exact reading isn't as important as they are all the same. Test the ohms from the white wires to ground, should read infinity.
On the feild coil measure from green to brown, should be around 4.5 ohms. test to ground too. Should be infinity.
If all these test prove good then it maybe voltage to the feild coil and reg/rec. Turn on the key engine stop switch off. Test battery voltage. test the voltage at thr brown wire at the feild coil cponnector and the brown wire at the reg/rec It should be within about .2 or .3 volts of the battery If not you have a weak connection somdewhere beteween tghe battery positive and the brown wire at the feild coil and reg/rec. Often diry contacts in the key switch, fuses, and connectors.
Leo

 

[arfstrom]

This model has a known flaw. The bike is 30 yo, and whether your reg/rec is fine, the test is too physically feel the wire, (right were its oil-ly, pending you bikes oil leaks.) The symptom is the wire turning brittle. The instructions Leo gave you is testing the stator, (the 3 white wires) If you look at Drewpies re-wire thread, you see what the shoddy wire looks like. it will feel brittle, you will hear crackling. Technically I am aware of a phenomenon where power effects the mid-path, creating a burn out zone. Well our burn-out zone is right where the stator wires come out of the engine zone, and bends up, to the first connector, under the seat.there is a four inch area where the brittleness is. so the wire is stranded, and is completely flexible on either side of the burn out zone.

 

[Xslille]

Hi, thanks all for your help.
I have done Leo's test. My battery was at 12.4v, was at 12v at 500 rpm and 2000 rpm. I don't know if bypassed rightly the reg since it didn't change anything in my readings. I basically inserted a cable in the White plastic thing that contains the connectors ( inserted in the green cable spot) and attached the other end to the lower engine part. I firstly unplugged the rec (green brown black) and connected the wire to the Rev green cable but then figured it should be connected.
Then I performed the stator check with the engine shut though, I got similar result for each three cables 8.8, 4.4 and 12. With the red lead from the ohmmeter connected to the red lead and checking blacks with the meter black lead I got nothing. Is it normal?
Still with the engine shut I checked the stator white cables, I got 0.9 / 0.8-1.1 / 0.9-1.1.
Again with the engine shut I got nothing out of the field coild green and brown..

Moreover I checked the cable going from under the engine to the battery box and it's true it sounds kind of 'crunchy'

Tanks again for your help, hope I'll find where my problem come from with the little knowledge I have, but with your huge help

 

[Xslille]

Hi, thanks all for your help.
I have done Leo's test. My battery was at 12.4v, was at 12v at 500 rpm and 2000 rpm. I don't know if bypassed rightly the reg since it didn't change anything in my readings. I basically inserted a cable in the White plastic thing that contains the connectors ( inserted in the green cable spot) and attached the other end to the lower engine part. I firstly unplugged the rec (green brown black) and connected the wire to the Rev green cable but then figured it should be connected.
Then I performed the stator check with the engine shut though, I got similar result for each three cables 8.8, 4.4 and 12. With the red lead from the ohmmeter connected to the red lead and checking whites with the meter black lead I got nothing. Is it normal?
Still with the engine shut I checked the stator white cables, I got 0.9 / 0.8-1.1 / 0.9-1.1.
Again with the engine shut I got nothing out of the field coild green and brown..

Moreover I checked the cable going from under the engine to the battery box and it's true it sounds kind of 'crunchy'

Tanks again for your help, hope I'll find where my problem come from with the little knowledge I have, but with your huge help

 

[Xslille]

Hi, thanks all for your help.
I have done Leo's test. My battery was at 12.4v, was at 12v at 500 rpm and 2000 rpm. I don't know if bypassed rightly the reg since it didn't change anything in my readings. I basically inserted a cable in the White plastic thing that contains the connectors ( inserted in the green cable spot) and attached the other end to the lower engine part. I firstly unplugged the rec (green brown black) and connected the wire to the Rev green cable but then figured it should be connected.
Then I performed the stator check with the engine shut though, I got similar result for each three cables 8.8, 4.4 and 12. With the red lead from the ohmmeter connected to the red lead and checking whites with the meter black lead I got nothing. Is it normal?
Still with the engine shut I checked the stator white cables, I got 0.9 / 0.8-1.1 / 0.9-1.1.
Again with the engine shut I got nothing out of the field coild green and brown..

Moreover I checked the cable going from under the engine to the battery box and it's true it sounds kind of 'crunchy'

Tanks again for your help, hope I'll find where my problem come from with the little knowledge I have, but with your huge help

 

[Scorpio1963]

Is there any pics on how this test can be done?I may or may not have a charging issue also and Im having a bit of a problem comprehending the write up.thanks Scorpio

 

[Scorpio1963]

Hi gang I have since developed an interest in reviving my bike again.I know for fact I have a charging issue.I have combination rectifier/regulator.Im going to start with that and see if this is where my problem stems from.Can I test it to find out out if its good or bad?

 

[XSLeo]

On a combined reg/rec you can test the rectifier half but not the regulator half.
In your repair manual there should be a description of how to test the rectifier on your bike. It consists of checking the ohms through all six diodes both ways then comparing the ohms one way versus the other.
If it's not in your book try Googling it.
The only way to test the regulator half is by swapping in a known good regulator.
Leo

 

[Scorpio1963]

Thanks Leo for chiming in,my unit is fully enclosed no way to check the diodes inside of it.Assuming its not bad the next step would be to check the stator wiring?

 

[XSLeo]

On the stator, as mentioned check the wire bundle coming out of the stator where it passes through the housing. If oil has leaked into the wire bundle it hardens the plastic and makes it brittle. This breaks up the plastic and lets the wires short to each other and ground.
If you find this to be true, replacing the wires may fix things.
Once that is done check the ohms on the three wires coming out of the stator. The exact reading isn't as important as they all being the same. They should read all the same and be close to specs. Use your lowest ohm scale. Most digital meters this will be 200. First touch the leads together, this gives you the reading of just the leads, remember this reading.
Now test the three wires, in your mind label tem 1,2 and 3. Teats the wires 1-2, 2-3 and 1-3. Now subtract the test lead reading from the test readings, as in lets say your leads reading was .7 ohms. Your wire readings were 1.5 ohms. 1.5-.7 = .8. The .8ohms is the actual reading. As I recall yours should be around .5 ohms.
Also test from the wires to the body of the stator, use a high ohm scale, like 20k. You should get an infinity, or no conductivity.
The first test tells you the windings are good, without any breaks. The second tells you if the windings are shorting to ground. On your field coil test from the brown to the green wire. Use the low ohm scale, should read about 5 ohms.
If these tests all check out ok check on the brown harness wire going to the field coil, it should have at or very close to battery voltage. This battery voltage is the one you find with the key and kill switch on. The brown wire should be within about .2 or.3 volts of the battery. If not your fuse connections, your key switch internal connections or any wiring connection between the battery and the brown wire are dirty.
Most wiring connections are easy to clean and tighten. Most switches can be taken apart and cleaned.
After cleaning a bit of dielectric grease will help prevent corrosion.
One thing you can do to test things is make up or buy some jumper wires with alligator clips on each end. Wirth the stator and field coil installed on the bike, reg/rec unplugged, field coil unplugged. Start the bike, use one of your jumper wires and to jump from battery positive to the brown field coil wire. jumper from the green field coil wire to ground. Now with your meter on an AC scale test the three wires coming from the stator. Same way you did the ohms test but on the AC scale. At idle each set of wires should put out about 10 volts AC, rev the engine and this should climb to around 20 volts AC. Again all three should read the same.
If you get good readings doing this try plugging the reg/rec and field coil wires back in. If the reg/rec is working as it should you should get good charging, around 12-13 volts on the battery at idle and around 14 - 14.5 at 3000, and at higher revs like 5-6000 it should not exceed the volts at 3000 roms.
Leo

 

[Scorpio1963]

Ok I`ll get on this today our weather is changing quickly Im losing days in which I can work outside.I should have started on this much soonerDam thing about it is I just done an oil change,how much oil am going to lose when i take the stator cover off?