Honda CX & GL M.C.C. (UK)
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Stator rewinding

Rewinding an armature is possible, but fairly involved; if you feel adventurous and are good with your hands, here goes. 

The alternator consists of a fixed armature or stator with permanent magnets rotating around it; the magnets are part of the flywheel at the rear of the camshaft. The armature is bolted to the rear case of the engine. 

I rewound one pole of the 250-watt armature on my GL650. It has 18 poles wound in three phases of 6 poles each, first phase at poles 1, 4, 7, etc, second phase at 2, 5, 8 etc and third phase at 3, 6, 9 etc. The windings of each phase are in series and in phase; the 'output' ends are the yellow wires at the three-way connector; the 'neutral' ends are connected together at the armature. Conductors are magnet wire (solid copper insulated with flexible varnish); diameter is 1.2 mm or 0.047 inch, corresponding to slightly smaller than 16 AWG. The CX500 is similar except that there are independent high-voltage windings for ignition in place of two poles. 

In my case, one pole had shorted to the armature; the epoxy that covered it was burnt black while the others were brown in colour. I confirmed the short by “growling” it, an AC test that motor rewinders use. Removing the epoxy revealed that the wire was cooked. 

I removed the winding and chipped away all the epoxy down to the bare armature, then soaked the whole thing in naphtha and brushed it clean, rinsed and repeated. Then painted three thin layers of epoxy on the armature to insulate the winding, allowing the epoxy to cure between coats to be sure I had covered it completely. I used Hysol 24-hour epoxy, which is fairly liquid, and cured each coat for 1 hour at 60C in a kitchen oven. Five-minute epoxy is too stiff to flow well, and does not allow enough working time. 

You can rewind just the burnt pole; no need to do the others if they are good. If necessary, stretch the new wire beforehand to remove kinks. Rewind the pole with the same number of turns, 24 turns in 3 layers of 8 in this case, and in the same direction; this is important. All windings must be in phase; make a diagram as you unwind the existing wire. Apply epoxy between layers to prevent the wire from vibrating in service; this is a messy job and requires three hands or some creative solutions using clamps to hold the wire tight. Finish by painting the entire winding with epoxy. Once the winding is cured, clean the wire ends with steel wool, then solder them to the existing wiring; use rosin-core solder. Finally cover the soldered connections with epoxy. A complete rewinding would be 18 times that operation, and I would rather not contemplate it. You will use 2 metres of wire per pole. I have since done 1500 Km on the repair and it is holding. 

A lot of work, but a big saving over an Electrex replacement. I believe someone on this forum has a link to a web page with pictures of the armature.