How to test the charging system?

Hishman

Hishman

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Hello. I have determined my charging system is kapooy. I have less volts from the battery when the bike is running. I've read the manual and it says to check the resistance of white and green wires ect. But for the life of me I have no idea what I'm supposed to be checking. I have the seat gas tank and alternator coil cover off and I still can't determine what needs to be tested. If someone could either very descriptively explain the locations for testing or post pictures that would be great!
 
Two common problems is the voltage reg. And or the wire from the stator. Don't worry about relays, down load the manual, print out bone or two pages of electrical stuff. (Reference). The go to Willem refresh of the tech page,or justgo the Tech page, and find the drewpy re-wire page, he has a section on just the stator stuff. That is all I did. Trouble every else first. Stator is the three white wires. Idk what bike you got. Find the wire diagram for your bike. I probably wasted money on the dual recifer/voltage regulator, so don't waste your $$. Check things out, use the various search functions, look at my photo albums, search others Google sites, YouTube has examples. Most of us don't touch the electrical, I don't mind it. Always double check recommendations. Via this web site, don't put yourself out on a limb, just cause your in a rush.

Good luck
 
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Updated profile with my bikes information. I didn't know the different models were different. I have a fully printed manual and IMO it sucks. Its not descriptive enough for someone with as little electrical experience as me
 
Are looking at the Haynes manual, or the factory manual? If you are using the factory manual and have a multi-meter, it shouldn't be too difficult:

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The resistance between any 2 white leads should be within 10% of .72 ohms. Just put one lead on one white, and the other lead on another white and do that so you test all three white wires with the other, so u-v, v-w, u-w- all should be within 10% of .72 ohms. If it tests out of range, either way, replace the armature.

Test resistance between green and green, one lead on each, should be within 15% of 4 ohms. If it tests out of range, replace the field coil.
 
Alright Im trying to figure this out. So far i have determined turning the key on does not excite the coil. I have less than 12v from the battery when bike is runningf, and no change with rpm. I checked the ohm's between the three white wires at the connector between the carbs and battery. Im not sure if that is the correct place to check the three white wires. The connector is not pictured below. Anyway i got about 1 ohm for all of them. A little high but they are all the same.

Moving on the picture below is what i believe is the voltage regulator(left connector) and rectifier(right connector). My next step is to bypass the voltage regulator. I have looked around and i can seem to get a clear answer



Do i need to run a wire from the green wire to the + side of the battery from the pic below. Also does the connector have to be plugged together or is it fine just to run the one wire from the green pin to the + side of the battery. I have also seen black to - side of battery. I'm just not sure what to do.

 
According to the manual excerpt from HoughMade, if the resistance between whites is more than 0.792, the alternator armature wiring is probably broken.
With such high readings, I think you need to just confirm it's broken and replace the armature. The fact that they are all the same @ 1.0 is not relevant.
 
I am willing to bet you, if you follow the bundle of white wires to the bottom of the engine, and test the flexiblity of those wires, Right there,Where it comes from the bottom exterior of the engine, and before it ascends to that plug you have a photo, it will be crispy. crackly, with a Pop.

Drewpy's rewire http://www.xs400.com/forum/showthread.php?t=5934
Drewcifer rewire http://www.xs400.com/forum/showthread.php?t=7616
Sbondini link http://www.xs400.com/forum/showthread.php?t=8435 (Drewpy had more time on this one)

Each thread has tips and advice, and we have it for free, just look around.

I was going to get the screen shots, Nope, They are there, just use rewire for a search word, and you can see the wonders of 30 year old wires
 
This bike was garage kept by it owner and even the seat is not cracked. I will not rule out bad wiring but I can easily bend both bundles of wires running under the bike back and forth. I've cleaned and inspected the connectors and they are all good. Right now I'm trying to test the regulator as I couldn't even get the ohm reading to show up on one test. I just can't get a clear answer as what to do to bypass it
 
If you don't want to follow the advice offered, why do you keep asking for it?

With the gracious assistance of members here, you have already found a common issue with the charging system, and have been offered advice on how to further test and fix it. Yet you insist on wanting to try testing other components that you have no knowledge of how to test.

That isn't cool... :(
 
I'm just asking how to bypass the regulator because it can be a sure fire deal if its working or not. I don't want to rewire the coil just yet as clearly the wires are in good shape visually. I just can't get a clear answer on the bypass. Does it not make sense that I want to test the one component that either will fix the problem or won't ruling it out or help determine it is the coil
 
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But the Yamaha book says if the ohm variance is more than 10%, "in either event the armature must be replaced".
Your variance is 39%. Why not start there?
 
Well I have determined the the po hooked some connectors up wrong. The field coil, stator neutral switch, oil pressure sensor were all looped together! I now see where a lot of my confusion is coming from as tracing leads just took me in circles, literaly. So I reswitched the connectors. My fuse box is falling apart so I'll have to fix that before moving in. I will likely get 4 inline fuses
 
Hishman said:
... the the po hooked some connectors ... in circles, literaly ...
Click to expand...
Well, that 'splains a lot Lucy.
At least you can blame the PO and not yourself at this point.
It's much more satisfying to correct a PO's mistake than one's own ;)
 
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http://www.xs400.com/media/albums/342/
Here is my voyage into replacing the inline block fuse with blades..

There is a couple of the wire diagrams for the 1980 g, I have seen some g owners seem to think the SH is more closer resembling what they have on their bikes. If your good at reading that type of stuff, It will help trying to figure out where to go next.
 
Alright i finally have some time to work on the bike. I took off the field coil and armature. I tested the file coil and it is 4.2ohm so its g2g and the wires are in good shape so i wont be messing with them. Now testing the armature, even at the very tips of the wire(just before entering the rubber grommet) it still reads .9ohm. Occiasonally it briefly drops down to .8ohm. I can see no evidence of a broken wire. Should i cut back they resin/cloth to expose where the wires enter the winding to see if there is a break there? I am also going to let it soak in soap/water solution.

Should i just buy a new armature? I can't see to source a new one. Id rather not buy a used piece if possible.
 
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Just learned something today. "meter lead resistance" and mine has .2-.3 ohm. That puts my armature and field coil in spec. Tmrw i will mount the coil and armature. My guess is its either the vr or rectifier.
 

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