For idle rpm the A-B-C voltages are probably typical. Usually the rpm would be 5000 and voltages more like 50 V AC.

Resistance measurement is from one yellow wire to chassis with rect/reg disconnected, not between yellow wires. You would be checking for a short or leakage to chassis for the stator.

Recommend you recheck the battery voltage after repairs to the connector block, need to confirm your "evening" voltage measurements were fictitious.

Update:

Fired her up at the weekend. Electrical measurements were good. I attribute the 'evening' results to 2 things:
1)Not actually reconnecting the reg/rec initially and
2) With one of the yellow wires at the reg/rec block, the spade was not fitting the tongue correctly.

On Sunday I went for a spin up past Kinloss to Findhorn, didn't wear enough layers and was absolutely freezing!
Bike felt good enough at speed (first time I've ridden it without the 33hp restriction) but was sluggish ,ie crap, at 20mph and below.

It's done 50 miles now and today I shat myself because it took 3 pushes of the button to start this afternoon.
I have paranoia about the electrics and about the plugs being fouled that will take a long time to shake off!

To that end I whipped out the rear plugs tonight fully expecting them to be soaking wet.
As a pleasant surprise they were in good nick, the electrodes were dry and the ideal brown/tan colour with no sign of blackening or sooty build-up. A little oil on the threads but just a spot. I think I'll be checking them weekly to be honest. I've always suspected that it runs rich but I couldn't say why exactly, probably because it idles crap and is poor at low speeds.

So the next concern should be idling and running at low speeds. It's pretty lumpy up to 20mph which might be alleviated by taking out the slack in the chain but I don't think that's the only cause. The idle also fluctuates if I try to set it to 1300 and the engine splutters, so it's set at about 1500 for now. I'm running standard jets and the pilot screws are at 2 1/4 so those should be fine. Guess that requires more expenditure (sigh) on a carb-tuner.

You might try checking butterfly settings on the carbies if you have not already.

magg wrote:You might try checking butterfly settings on the carbies if you have not already.

Aye, I checked those over winter using feeler gauges and got it as close as I could by eye. I'll check the rubber flap as well but I'm confident that it's positioned correctly.

A twist drill is an easier if not more accurate way to check/set the butterflies, the round shape is a better match to the round profile of the venturi. If it idles better at 1500 that's ok, mine is same. Lumpy throttle at walking speed is pretty normal IMO, no cush drive, chain a little loose and vacuum carbies all tend to exacerbate the problem. Helps to teach one smooth throttle control.

Good arrows on getting it sorted!

Thanks Mark. Shall I sling you some coin for the plugs? Another alternative is free publicity- I was planning a plain red respray, maybe with a big 400GB decal on the fairing?

I've noticed a difference on start-up. I've gone from 33bhp and 110s all round to no washers and 115/118s. Previously the revs would build and then fly to 4-5K before I backed off the choke, but now they only creep towards 4K after a good 20-30 seconds.

It is all good mate, glad it works and I am a firm believer in what go around come around

This is interesting. My right headlamp only comes on if I switch to full-beam. That's a new one on me!

Check the right headlamp bulb, may be just the low beam filament has failed.