[Mart]

Well I tried tweaking the cut in, it kind of worked a bit then it stopped charging completely.

I fitted the known good generator off Old Rusty, and that didn't work either, so I fitted the other voltage regulator and that combo works perfectly, cutting in just above idle, and charging strongly.

I laid out 5 generators, some of which I presume are 12V, and some presumed 6V.

The 6V ones measure approx 4 ohms through the field windings. The "12V" ones seen to come out at 8 or 9 ohms.

Funny thing is, the known good one that charges really well checks out at 18 ohms.

I can't work out quite what is going on, should a 12V one be 18 ohms or so, and all the others are 6V?

I don't think so. maybe the higher reading was due to it just having run and being warmer? It didn't feel more than slightly warm to the touch though.

One thing I can see, is that the pulley on the good one is a bit smaller than the others. That must help.

Not really any wiser.

Mart.