charging sys.

[willieboy62]

first off sorry I know there is lots on this subject already
So here is what i got, 1982 yamaha xs400
ohm checked stator three white wires (engine cold) 1.1 ohms all wires (little off book says .75 ohms plus or minus 10%)
next test book says field windings two green wires but my wires dif. color
i forget right now but i did get a 4.0 reading @ that connector. book says past
next test rectifier from red to white wires no reading one way and continuity
other way same with the black wire (tested good)
So I did clean all connection and put back to gather.
I have new and charged battery I tried to bypass voltage regulator
by putting battery voltage to green wire still no charging.
thanks,

 

[bcware]

Go with the 3 white wires first. 10% of 0.75 is 0.075 for a range of 0.675 to 0.825. Thus a reading of 1.1 is 46% off.

1.1 - 0.75 = 0.35
0.35 / 0.75 = 0.46
0.46 * 100 = 46%

 

[ThePsuedoMonkey]

don't worry too much about the precision of the resistance readings: most pocket multimeters have quite a bit a error for the small values. Mine reads ~0.78 with the probes shorted. Do you get an AV voltage between the white wires and ground while running?

 

[willieboy62]

thanks for the info. as soon as i get a chance I will check for a/c voltage @ white wires.
Just so I am clear thats with connector from stator unpluged and meter to groung is there a spec. of how much a/c voltage?
thanks,

 

[ThePsuedoMonkey]

I left the stator connected to the rectifier. There isn't any specified AC voltage, but the measured RMS voltage will need to be more than the open circuit voltage of the battery plus the forward voltage of the diodes used in the rectifier. So 12.5V on the battery and 1.1FV on the diodes means the stator needs to give off an RMS voltage of at least 13.6V AC in order to charge the battery at all.

 

[Drewcifer]

Im guessing it' time to take off your stator cover and see if it's damaged at the wires where they all seem to be after 30 years. Drewpy's how to rewire on the front page covers it, as does my recent write up:

http://www.xs400.com/forum/showthread.php?p=79878#post79878

Don't be intimidated. It's an easy find/easy fix solution. We did just have a member with damaged stator and he found a replacement stator and motor in the same place and he's riding again. We'll get you through this.

 

[Drewcifer]

willieboy, any progress?

 

[1979XS4002-F]

IDK about Willie but Im in the same boat...Rectifier tested out fine according to manual "test"..all open one way, all closed the other...Brand new voltage reg from oregon cycle installed, battery charged to 12.6volts, stator/field coil test shows Im good on resistance between whites and the grn/grn(blk on my bike)..cant rem the readings but they were on spec according to manual. Yet, when I start it and rev it up I only get .1 or .2 volts increase...Connections looks good, disconnected all and checked for corrosion and reconnected. Dont know how true the theory of the feeler gauge test to stator/field coil and turning the key on and then the feeler stick to the stator/field coil but it works on my CB750 and does NOT on my XS400...an idea what I can try next?

 

[Drewcifer]

You can simply see if a single edged razor blade is held to the stator cover by the field coils magnetic field. If not, it's probably not supplying the "fuel" voltage needed to charge the battery.

And by the way, the first time I worked on my bike I found a pretty embarrassing thing had happened. I had connected my wiring on my new voltage regulator to the old dead one instead of the wiring loom. It was very late at night but I was pretty humbled that I'd focused so hard on soldering that I missed what I was soldering to. It happens.

So recheck all the wires. My replacement voltage reg didn't work until I soldered it into my loom. No connectors, no bullets, no crimps.

 

[willieboy62]

willieboy, any progress?

Sorry didn't get back to you, I may not get to check the bike tell saturday.
been busy with work. but thanks for the info and I will let you know what I find.
I was going to check a/c voltage from stator and then maybe pull the stator cover
and insp. So is there a chance it will need rewound or replaced. If so how will i be able to tell.
Maybe just cleaned up and new wires? If the stator checks ok should I try a new voltage regulator?
weather is getting nice here NW.

 

[1979XS4002-F]

You can simply see if a single edged razor blade is held to the stator cover by the field coils magnetic field. If not, it's probably not supplying the "fuel" voltage needed to charge the battery.

And by the way, the first time I worked on my bike I found a pretty embarrassing thing had happened. I had connected my wiring on my new voltage regulator to the old dead one instead of the wiring loom. It was very late at night but I was pretty humbled that I'd focused so hard on soldering that I missed what I was soldering to. It happens.

So recheck all the wires. My replacement voltage reg didn't work until I soldered it into my loom. No connectors, no bullets, no crimps.

Drew...lol, humbling indeed.. I have done a many of those similar "things".. Back to the voltage reg..The razor blade test was done with a feeler gauge..no stick.. I did however remove the old Vreg before installing the new and re-soldered the new into place and shrink tube'd them as well...I did stumble on your old post(i think it was yours) regarding the by-pass trick, awesome detail Sir, going to try it out and see results..I hope my new Vreg isnt he issue after spending $50 on her Thanks thus far, always nice when I see a reply waiting

 

[1979XS4002-F]

You can simply see if a single edged razor blade is held to the stator cover by the field coils magnetic field. If not, it's probably not supplying the "fuel" voltage needed to charge the battery.

And by the way, the first time I worked on my bike I found a pretty embarrassing thing had happened. I had connected my wiring on my new voltage regulator to the old dead one instead of the wiring loom. It was very late at night but I was pretty humbled that I'd focused so hard on soldering that I missed what I was soldering to. It happens.

So recheck all the wires. My replacement voltage reg didn't work until I soldered it into my loom. No connectors, no bullets, no crimps.

Ok, SO the Vreg test failed..dammit,,,no increase in voltage and no magnetism..dammit! I suppose I should be pulling the field coil and inspecting wires/winding?

 

[bcware]

The 3 white wires on my bike got pinched between the front sprocket cover. There is only a small hole for the wires to travel through; if you aren't looking they can easily find their way out of this space and get pinched when the cover goes back on.

 

[willieboy62]

willieboy, any progress?

Hi all, so drewcifer I have stator and coil out of the bike and was looking at your post where you cleaned and rewired the stator did you rewire coil also, guess thats what it's called mine has a green wire and a black wire that look in about the same shape as the three white wires. Is there any thing else I should be looking for while I am in there?
so far I dont see the smoking gun here but will replace the white wires with butt connectors and shrink tubing and soldering. I was wondering what gauge wire did you use, think i have 12 and 16 gauge,
thanks, hoping you are sitting @ your computer waiting for this post so you can reply LOL! thanks again! <--- wish that was me today

 

[Drewcifer]

WILLIEBOY : hey buddy, yeah, I tend to reply around this time, 8 or 9pm Pacific time.

So you wanna measure the white wires of the stator to each other. Sounds dumb but measure to see if you get more or no resistance between white wire one and two, and white wire one and three (etc....) They should all be about the same. Mine were all the same, they were WAY OVER. 1.6 ohms I think. Bike runs fine. They just get old and run outside the ideal.

For your field coil you measure between your black and green wire, and should get like...4 ohms I want to say? It's in the manual you can get off the front page. Mine was 5.5 ohms and again, it still works fine.

Now as you saw in my post:
My white wires had grubby fiber over them, like a woven messy oily gunk. Slid that back and I saw clean exposed wire! Not good.

I went to the boating store up the street thanks to Drewpy and got 16 gauge. It was way too thick! Easily could have gotten away with 18 gauge. (higher numbers is thinner I believe) Drewpy did PM that 18 was fine but I didn't get home to read it until I'd bought the 8 feet of 16 tinned thinwall. 18 will do ya.

My trick that helped a few guys was to overlap the wires at 45 degrees and then nip off the excess when you solder them. They need to bend up from the stator and then fit through the rubber grommet thing, and if they're straight they'll never go, so go ahead and solder them "crooked" so they reach up and then bend as they leave the grommet. Works like a charm. I no longer trust anything but solder itself. Connectors look connected but fail.

Make sure you get continuity on the wire that leaves the voltage reg in the wiring loom and goes to the field coil connection block. I tested mine to be sure I had no other breaks in my system, but they were fine. What I had was a bad set of bullets I'd crimped that were vibrating loose. And the aforementioned lovely soldering job to the dead voltage reg....ahem.

So you can do that shiz for now. Did you ever get magnetism from your field coil? We need to know that too....

1979XS400: I think if your bike flopped the field coil test then it's your regulator to start. I can't vouch for Oregon Cycles but aftermarkets are avail for 25 max so if you wanna do that swap, I'd look on xs650.com. They cover it there. I did it in my write up too. But you need to get real cozy with your voltmeter and watch MRMAXSTOREY on youtube. He has a how to read wiring diagrams on motorcycles that will get you going and feeling really smart after you watch.

Hang in there for now chaps. We'll get you back up soon!

 

[willieboy62]

Rewired stator today, still no A/C voltage
wondering what I am missing, hmmm, is there something magnetic
with the stator or coil, or not on this style charging system?
Just asking cause when I was in there didnt seem like anything was magnetized.
ohm readings are pretty good (coil 4.0 ohms) and (stator .8 ohms) I did see
some wear on inside of flywheel, I could see copper looking wear
I did buy a voltage reg. for it but dont see a need to use it because no stator out put
and if i try to bypass reg still nothing. any thoughts on my problem is greatly
appreciate! almost ready to trade for newer bike that is charging

 

[Drewcifer]

I think in this case we might need a picture of what you're looking at Willieboy. Something isn't adding up. Must be communication.

Can you throw light on the stator and coil and snap a pic and post it here? You'll need to upload it to your album on the forum and then post the code link below it in the album into a post and it will appear here in the thread.

 

[drewpy]

Rewired stator today, still no A/C voltage
wondering what I am missing, hmmm, is there something magnetic
with the stator or coil, or not on this style charging system?
Just asking cause when I was in there didnt seem like anything was magnetized.
ohm readings are pretty good (coil 4.0 ohms) and (stator .8 ohms) I did see
some wear on inside of flywheel, I could see copper looking wear
I did buy a voltage reg. for it but dont see a need to use it because no stator out put
and if i try to bypass reg still nothing. any thoughts on my problem is greatly
appreciate! almost ready to trade for newer bike that is charging

you need a voltage regulator to provide a regulated power source to "magnetize" the field coil.
This then, through induction translates to AC power through the stator back to the battery via the white wires and is converted to DC by the rectifier.

Its a simple system, just make sure enough volts are going to the field coil and the rectifier is converted the AC to DC

 

[Drewcifer]

Yeah, the magnetic part of our system is a spool of wire called the "field coil" it's just a simple electromagnet. When DC volts go around a spool of copper wire a magnetic field is created. We need to find out why you have no magnetic field. Do you have a multimeter to check the wires with? OR a car test light?

Let us know.

Drewcifer

 

[willieboy62]

Hi all
update on charging sys. So checking the field coil green wire and black wire
@ connector they both show positive battery volts, dont sound right.
so i unplug the connector bike running, with power probe put power positive
to the green wire to coil and ground the black wire and bike starts charging about
14 volts but if I try to ground the coil connector plugged in bike dont like it pops breaker on power probe and voltage goes way down. I did wire the new regulator
in just to see if something (ground) was missing but no differance. I know I am getting closer to my problem. What i dont undestand is that black wire I am
grounding turns to a brown wire and looks like it goes to the regulator and power from fuse, will in my wiring diag. Thanks for taking the time to reply! <--- this will be me soon!
thanks,