How To Clean Alternator Windings

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Is it ok to soak this and the rotor in degreaser and brush if off? I'm doing a complete rebuild for the first time and don't want to screw it up.
not to sure ,but i dont think so maybe someone else has better info for you.
Travis Staff Member XS650.com Supporter

I would think that as long the degreaser you use doesn't eat the epoxy coating you should be ok. So I guess it depends on what you use to clean it.
There is nothing to be gained by cleaning the stator. You risk having the cleaning solution damage or remove the very delicate and old (30 years) enamel coating on the wires and causing a short. Just leave it as is.
+1, with the note that taking a soft brass brush to the commutators for a couple of swipes couldn't hurt, and will help new brushes seat better. Just don't go crazy, and no power tools. AND BRASS, not steel brush.
In fact, forget everything i just said.
sundie,
Well, the best thing to use on the rotor slip rings is a pencil eraser. Any scratches on the slip rings will make short work of the very soft brushes.
can the rotor go bad? i heard that you test it with an ohm meeter between the 2 circles and that it shouldn't go over 5 ohms.
Use some Meths on the rings or rubbing alcohol, degrease the rest IF you must with mild detergent .
Yes, rotors can and DO go bad. Usually because of age, or corroded wiring creating resistance, which create more load on the whole system. 5-6 ohm's resistance is the proper spec for the rotor, between the 2 slip rings, without the brushes contacting any part of the rotor. Too much resistance is usually a sign of trouble coming, not enough,the rotor is starting to short out. There should be no connection between either slip ring and the body of the rotor.
ok. just wondering cuz the rotor on my 79 doesnt read any resistance. but it was one of those "i better ask to make sure"
but a friend of mine is having trouble with his charging system and i tested it earlier today going with the 5 ohm spec. currently its at 5.2 ohms. so were thinking its the rectifier/regulator pack.
On the home page is a lnk for the factory owners manual. That will give you step by step instruction on how to properly diagnose your (his) charging system.
XSLeo XS650 Guru Top Contributor

Quite often the brushes are the reason for a non charging problem. They are about the least expencize parts to replace. Try that first.
Back to the original question: Neither the rotor nor the stator should be cleaned in any way shape or form. The 30 year old wire is only insulated with a thin coating of enamel and it can be easily damaged with any cleaning method. Just leave the dirt on them.
If you just have to clean something, then clean the spokes.

lakeview and DaveO like this.
I blew mine out with compressed air and wiped off the worst of the grease with a soft rag, but that's all.
Leo or anyone, can my 75 run without the brushes mounted? I just put in new brushes without any result, then i disconected and found only 1 ohm at rotor. And it wont run!
gggGary On the road of life I'm a speed bump. XS650.com Supporter Top Contributor

Yes, you do not need a charging system to run, just a charged up battery. You can't "ride" it but it will "run" with no charging system.
gggGary On the road of life I'm a speed bump. XS650.com Supporter Top Contributor

I keep a spray bottle of Mineral spirits and spray that on about everything, brush with various brushes, and rag or blow dry with compressed air. If electric parts are covered in oil and dirt it's best to clean them.
Well, I still think that this is valid. Cleaning the stator or rotor windings does not make them work better but the potential for damage is there.
your best bet is to replace the brushes and use electric contact cleaner I used it on my 77 xs650 and it seemed to work fine thanks dave
XSLeo XS650 Guru Top Contributor

On the not running without the brushes, yes it will run but it won't charge the battery. You can start with a fully charged battery and with the charging system disabled by removing the brushes or unplugging the reg/rec it can run for a short period.
Until the battery discharges enough so the ignition can't fire.
This is a racing trick, removing the stator and rotor and running on just a battery. This removes the weight on the crank allowing faster revs. The bike runs fine for the few hours of a race but not much longer. Not very practical on the street.
Leo