Yep, 70-80V across all the pairs... There's other tests but they all seem to be only for finding out why you're not getting the expected readings at the reg/rec connector. To ebay I go!

Northy, first off apologies about not getting back to you on the other thread, had my head where it shouldn't be all this week due to work. I see you've now sort of solved that though.

The voltage should, as others say, rise when you stick some revs through it. Move revs, more alternator charge, more output from the reg/rect.

My first instinct was that the alternator wasn't doing it's job properly. But you say the alternator wires are giving approximate (if a little low) correct values. TBH, I'm not sure what the specific values are for the SV, but 70-90V sounds about right for a bike.

Other than that, the battery. I have seen it in a lead acid battery that was almost dry, and they can dry up because of charging issues. Worth a check if you haven't already.