Re-wiring stator on an 81 xs400

D-Run

D-Run

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Hey everyone!

I'm in need of some help. I recently attempted to rewire a stator for my 81 xs400 and it was a failure. I'm just looking for some advice, tips, tricks and helpful guidance. Some questions right off the bat are:

what gauge wire to use? 16 or 18?
why do both of the stators I have have four white wires and all of the manuals I have talk about testing procedures for three white wire? what is that fourth used for? At the wire connector that fourth wire doesn't pair up with another wire.
 
Sorry the regulator & rectifier didn't help. Did the other parts do what you wanted?? Also there are a couple how too's on the site on how to rewire or repair your stator. I think there's 1 from Drewpy in England?? that should have just what you need. If I remember he had to repair the wiring that came off the stator and there were some issues with wire size and insulation. Here's another thought. If there's an electric motor repair shop or possibly an alternator & starter shop they might be able to help. Did you actually check the Ohms across the stators windings? I still haven't found my crap(Haynes) manual yet but there's also a section here with the resistance values for it.
 
No worries. The other parts I got from you worked perfectly!!! Thank you for them! I'll have to find the how too from Drewpy. I did look at the ohms and all three wire are reading 0.9 ohms when they should be at 0.72 ohms. I'm guessing I screwed something up rewiring it. I'lm getting pretty quick at taking everything apart now. So back out the stator will come and I'll give it another go. I never though of a bring it to a repair shop. I'm not sure where one would be around Duluth. But I"m sure that has to be one somewhere.

Thanks for the input!
 
If they all read the same at .9 you might be ok.
Does the meter read higher than zero if you touch the two leads togther? If so you'll need to subtract it from the reading on the stator leads to get a more accurate result.

The fourth wire isn't used on all bikes. If your harness doesn't have a fourth wire then you don't need it. Some years used it for the headlight relay.

As for wire size. The bigger the better, within reason. Drewpy used 1.5mm, apparently that's what the stock size was. Equivalent to 16 awg.
http://www.xs400.com/threads/rewire-how-to.5934/
 
Glad to hear those other parts worked for you. I would figure that there's a few electric motor repair shops in the industrial area near the docks. Or even across the bridge in Superior. I know we've seen some years ago when we first drove there before we were married. I think they were on Superior st behind where the Electric Fetus was or possibly around the Railroad Museum. You'd think they'd be all over town since there's lots of electric motors used in the shipping industry. You might also need to re visit all of your electrical connections specially round the fuse box to the regulator / rectifier and then the starter solenoid.
 
Looking at your previous post thinking while your resistance is only .2 over the required value you might have your windings a little oil soaked. I would try to clean your stator in something that will remove the oils & grease that seems to collect on them. I'm not sure if this will help but I'd be willing to give it a shot. I think soaking it in something like Simple Green might work. Just dilute it as for regular cleaning I think 1 oz / gal. hen when you've removed it from the cleaner put it in a very low oven around 200 should work for 45 minutes.
 
So here's an update for everyone. I rewired the stator, again. Installed it and still had the same results. I'm kinda frustrated at this point. But I began looking at the wiring diagram and notice/remembered that one of the white wire splits off and has a diode inserted and goes to the headlight relay. So I decided what the hell I'll unplug the headlight relay and see what happens. Well shit, that dramatically helped! At 4000 rpm I'm getting 13.5 volts roughly.

But now......why would the headlight relay be causing this???? I have switched the the relay with known good ones and I get the same results, 12.25 at 4000 rpm. I did have the diode that is connected to this white wire burn out on me and I have to admit that I just replaced it with a section of wire. Could not have a diode in place be causing this issue???

Any suggestion, solution or advice is greatly appreciated. I'm hoping to solve this before the weekend. It's suppose to be really good riding weather.
Thanks again
 
Well it'd draw roughly twice the power without the diode, so yeah, I'd get a replacement in there.
Not sure what's been used as a replacement. The stators can put out 70+VAC at high revs so you'll need one with a high voltage rating. Shouldn't have to pass much current though.
Might be a thread with better info but I'd think something like this would be OK:
https://www.radioshack.com/products/3-amp-200v-barrel-diodes?variant=5717580037
Not sure how the relay would behave when fed AC instead of DC but I wouldn't do it much more
 
Okay the Diode is attempting to keep the electric current to DC. otherwise the Stator creates electricity in AC (alternating current). Now the relay for the headlight has a diode in it as well. perhaps that one is shot? I hate to think bad, since I did, and ordered a new one, and the new one was not going to fit with out some rigging. I found out my old one was fine shortly after that. Now that said, sometimes some abuse to the wire harness can zap your diode. I guess.Give it a shot. good luck.
Tobie
 
Since we're talking about the diode I thought I'd have a look at mine. Hadn't looked too closely yet since it's not on the bike.

Apparently it exploded while the PO had it. Disintegrated when I touched it.
I'll be in the same replacement boat soon.

If there's a diode in the relay itself it might not be for rectification purposes. I'd have to see how it's wired but as far as I know my relay works so I won't be taking it apart quite yet.
 
Update......replaced the diode and still had the same issue. I started to think a little bit on how to trouble shoot this and narrow the problem area down. So what I did was disconnect the wire from the diode and it charges better.....13.5 volts @ 4000 rpm. When I plug that white wire back in the charging voltage drops to around 12.25 volts...or so. So then I left the white wire plugged into the diode and disconnected the headlight relay and the charging voltage goes back up to 13.5 volts @ 4000 rpm. I haven't tried anything else. I'm kinda stumped where to go from here. But in my opinion 13.5 volts is a hell of a lot better than what it was at. Any ideas guys?????
 

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Stock on his 81 would have been a fully electrical regulator, non-adjustable.

How big is that regulator, arf?
 
Diodes only allow electricity to flow in one direction. stops any feedback into the stator.
I would suspect that the reg/erc needs looking at as that feeds the field coil with a varying amount of current.

How is your battery? this system needs a good battery to function properly. (usually they are around 13v dc)
 
BBS....the headlight comes on as soon as I turn the key.

Drewpy.....the battery is....let me think.....I bought it last year when I got the bike.

What about that white wire leading to the headlight relay. Everything goes to shit when I connect. That's what is really confusing me. The relay must also be getting power from the red/yellow wire which comes from the fuse box. Which in return will still allow the headlight relay to operate.
 
my next step, i'm thinking, is to revisit the reg and rec and also the battery. Maybe chase some wires?
 
There are two current threads on the headlight relay right now and it's confusing....

It's the white wire that initially allows the relay to turn on. Without it the relay will never turn on.
Once the relay is on it back feeds itself from the red/yellow wire, keeping itself on, but without that white wire to turn it on the first time nothing will ever happen.

See: http://www.xs400.com/threads/headlight-relay-replacement.15720/

Disconnecting the diode vs disconnecting the relay is basically the same thing, since the wire from the diode connects directly to the relay.

I'm still not convinced that there's any problem with the headlight or relay at all but if something in the headlight/relay circuit is causing an excessive current draw you can narrow it down.
Disconnect the headlight before starting. If the drop goes away it's just the headlight. If it stays it's the relay itself.
I suspect you're just seeing the drop from the headlight.

Any word on the stator resistance readings? Did you figure out whether the meter leads have a resistance above zero when connected together?
Have you tested the field coil?
I'd download the manual above or the Haynes manual available in the manuals thread and go through everything in the Electrical chapter.
 
D-Run said:
BBS....the headlight comes on as soon as I turn the key.

Drewpy.....the battery is....let me think.....I bought it last year when I got the bike.

What about that white wire leading to the headlight relay. Everything goes to shit when I connect. That's what is really confusing me. The relay must also be getting power from the red/yellow wire which comes from the fuse box. Which in return will still allow the headlight relay to operate.
Click to expand...

the light should come on when the engine starts. the white wire from stator is the "engine on" feed to activate the relay. relay does need a +ve supply for when the relay is activated
 
So what would you think is causing the headlight to come on? Right now I have the white wire unplugged and the headlight still comes on.
 

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