Left hand alternator stator.

Hi Gents,
The restoration is going well with many parts now refurbished ready for reassembly. Next job is to take off the crankcase covers to get them rechromed. Started on the right hand side and the only real problem was getting the gaskets off. Got round to taking off the left hand cover and noticed this black residue on the stator. It breaks off in peices and crumbles into smaller bits when rolled between your fingers. Could anyone tell me what the likely cause is.

I'll leave this for Scotch to answer your question. He just had his hands on the stator and voltage regulator on his machine 2 weeks ago. I could answer but I'm sure Scotch's answer will be more thorough. No sense having it answered twice.

Well; I don't know about "thorough" but, I'd suggest it's what's left of the epoxy coating that some manufacturers use on their windings. My previous stator looked much the same.

Looks like the stator overheated- maybe too much current draw. Is it putting out any voltage ?

Looks like that stator is well cooked. I'd be shocked if it was still charging and if it is it won't be for long. A quick and dirty check for continuity between the windings and the casing will probably tell you for sure. With the continuity function on a multimeter, check place the probes on each of the three wire ends and see if there is continuity between any pair and/or the casing. If so it is most definitely fried. If not, I still wouldn't put it back in as its not long for the world.

Lots of things can fry them. A short on any of the windings, a bad regulator/rectifier, bad wiring, a bad battery, too much current draw. A common problem with many bikes.

This is what mine looked like.

Hi Gents,

Thanks for the quick responses. The bike was bought as a non runner but I did have it running briefly before I stripped the bike down so no chance to check the output from the alternator. I'll check for continuity and let you know how I get on.