Defective battery or charging problem or other?

[billdn]

The three yellows are the output of the alternator. You do have the engine running don’t you?
Oops didn't have engine running but no tried it and still no reading

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[billdn]

Reason for testing this way is if you do not have full battery voltage into the field coil (whie wire) you will not get the full output of the stator, you will get an output but not full output.

And your clip on ammeter is fine but they are not that accurate, should show you if its charging tho'
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Scores on the doors Bryan
Battery 12.2v
To regulator black wire 0.45v
To headlamp black wire 0.73 v
To black on ignition block 0.70v
To red on ignition block 0.49v
Hope that helps ?
Cheers
Bill

[billdn]

Further to test on 3 yellow alternator wires reads 0 when engine running but goes to 10 .8 between any pair if lights turned on but back to 0 if turned off?

[Bryanj]

You need to strip and clean the ignition switch as half a volt lost red to black is excessive.
With yellow wires disconnected but white wire connected you should get 20-50 valts AC accross each three pairs of yellow wires with engine running

[mike the bike]

Voltage measurements are usually made with respect to earth.  What voltages have you got on the voltage regulator?

[billdn]

Bryan
Just ease yellow wires out of block I presume to do check on white wire?

[billdn]

Mike
Sorry not with you on checking voltage regulator , how would I do that?

[Bryanj]

Easier to remove whole block and put a couple of jumpers in for white and green.

Testing is more normally done leaving the black test wire on battery -ve and testing for voltage with red test lead.
On regulator test for battery voltage at black then white

[mike the bike]

There's 3 wires on the voltage reg, what's the voltage on them?

[billdn]

Bryan
Made up leads for green and white but when disconnected block wouldn't start -no power I guess, should I start then disconnect block and add leads then?

[billdn]

Mike/Bryan
Voltage regulator check
Battery 12.2v
Black wire on regulator 11.7v
White wire.    "                  0v
Green wire.    "                  0v

[billdn]

As battery low, put on charged spare and as I had spare ( used) regulator thought I'd swap around to see if any difference, please see below
Regulator 1
Battery volts engine running 12.59v
Black wire on regulator 12 .12v
White wire 0 v
Green wire 0 v
Regulator 2
Battery engine running 12.60v
Black wire 12.2v
White wire 3.4v
Green wire 0v

Now I'm really confused , ignition switch strip next ps still no horn but guess related to switch?

[Bryanj]

Regulator 1 has a fault, Regulator 2 needs the contacts cleaning and somewhere between battery +ve and black at reg is a corroded or bad connector, try cleaning ign switch contacts and retest

[mike the bike]

Try shorting the white (regulator output) to black (supply).  You'll probably find the battery now charges.  Don't leave it shorted, this is only a test.  You don't want to cook your battery.
If it goes as I've suspected,  you need a new regulator.
You can use a combined rectifier/regulator.

[billdn]

Thanks Bryan,
just out of interest what voltage should I  be looking at regulator black, green and white for future reference. Ignition switch removed, please please don't ask me to to do that again , that was a devil getting that out and back. Ignition switch is about 7-8 years old as having been replaced before but looked ok and cleaned up terminals to ignition connector block.
Did you see message yesterday about testing yellow wires and using jumpers for white and green - was i doing something wrong?