Hoking up stator causes huge voltage drop, bike wont charge, HELP!?

[79xs]

Like the title says, when I hook up the green wire coming from my regulator to the positive brush on the stator the voltage at the battery drops to 9.5v. (my battery is brand new and fully charged, and reads 12.6 volts when the green wire is un-hooked and when the battery is out of the bike)

The voltage at the battery, ignition switch, main fuse, and regulator feed all drop from 12.6 v to 9.5 volts when I hook up the green wire. (my regulator is brand new, and I have tried it with both a new mechanical and solid state regulator)

I also did a regulator bypass, by completely unplugging the regulator and using a jumper wite from the battery + to the positive brush of the stator. I still get the bike wide drop from 12.6 v to 9.5 v. This drop happens regardless of whether the stator is plugged in (the plug with the 3 white, 1 red, and 1 black wires).

The resistance across the 3 white wires checks out. I read that there should be infinite resistance between the white wires and the stator housing, but on mine i get readings of 20-50 ohms.

I tink my stator is shorted / grounded out. Has anyone experienced something like this???

Thanks

 

[pamcopete]

79xs,

I think you are talking about your rotor, not the stator? The rotor rotates.

 

[Gordon]

79,
I am with Pete on this. Remove your brush's and check the resistance where the brush's rub on the rotor. The reading should be 5-6 ohm between the ring's, and infinity between each ring and the body of the rotor. As long as you have continuity between all 3 white wire's on the stater, and again infinity to the case of the stater, that should be ok. What your describing is a shorted rotor. Thats the one thats rotate's whith the engine.

 

[79xs]

I have 5.5 ohms between the slip rings on the rotor, I already checked that. I my bike also passes the 'slap test' and it generates magnetism when the key is on... and as far as I know the rotor is responsible for the magnetic field. I think my rotor is good.

I do have continuity between the 3 white stator wires, but i have VERY LOW ohm readings between the stator white wires and the case / stator housing. This reading should be infinity, so I think my stator is bad.

I have heard no mention of a voltage drop like mine when applying power to the positive brush, has anyone heard of this?

 

[pamcopete]

79xs,

You have to disconnect the yellow wire that goes from the common center of the three stator windings to the safety relay. If the yellow wire is still connected, you will actually be reading the coil resistance of the safety relay to ground. Also, stators rarely fail.

Also, if you do have a voltage drop when you connect the stator, then you probably have a shorted diode in the rectifier.

 

[Gordon]

Yea, Pete is correct again. I forgot about the yellow wire. What you can try is a battery from your lawn mower or car, just use jumper cable's. I have seen brand-new batteries that were junk from the store. Your rotor is measureing out good, so it's probably not shorted. It does take allot of amps to power up the rotor, but not that much to cause a battery to drop that amount. Oh wait, do you have a full size battery installed? Not one of those small batteries they use for kick only, minimal electric thing's, right? Like Pete said, leave the regulator unplugged and then check your draw. One more question, did you do the rec/reg mod that is posted in the sticky's? Did you replace the ground screw on the other brush with the nylon one? When that mod is done, the brush thats normally grounded is no longer grounded, because the ground now is in the rec/reg assy.

 

[79xs]

I tried my brand new full size battery for the XS, the battery for my car (Mini Cooper), and the battery for my Shovelhead Harley. Jumping the + battery terminal to the positive brush causes a voltage drop on ALL batteries I tested.

I did NOT so the rec/reg mod with the nylon screws. I went the expensive route and ordered the solid state replacements for each from Mike's XS. Both the rec and reg bench test ok, and my bike used to charge just fine using these components. I just delevoped this not charging and voltage drop problem during ride a few weeks ago, and ny rec and reg are only a few weeks old.

As for the shorted diode, I completely removed the regulator and rectifier from the bike, and jumped the positive brush to the + battery and still got the voltage drop. So, even with everything unhooked and removed, i still get the voltage drop. Could this still be by rectifier even if it is removed? Does it need to be hooked up in order to properly test the stator?

I'm pretty convinced that my rotor is ok. Its resistance checks out and it makes a magnetic field with the key switched on...

 

[XSLeo]

Ok, one way to test the stator is to unplug the regulator and rectifier. With the engine idling jump power from battery positive to the gren wire brush, this maxes out the rotor chrage. Now use your volt meter on the ac setting. read the out put of the three white wires from the stator. On mine I got about 20 volts between each pair of white wires.
Now plug the rectifier in. Jump the brushes and check the white wires voltage by back probing the plug in. each white wire pair shoulkd read better than 10 volts ac.
Now with the red wire from the rectifier unplugged from the battery, jumper inplace, at idle you should get better than 15 or 16 volts dc on the red wire to ground.
If not then check your grounds. If that don't help it sounds like the recifier has a shorted diode.
Being you got parts from Mike's you can't get them replaced without buying new.
I would spend the $6.58 at Radio Shack and Build the replacement rectifier.
If this fixes the problem, then you know the rectifier was bad, If it doesn't then try a different stator.
By the way I know the rectifier can be bench tested but I don't know of a way to bench test the regulator, how did you test the regulator?
Leo