Stopped charging

[BSA500]

The first thing I suggest you establish is whether any current is getting to the ammeter via the brown/white cable.

Presuming that the regulator red cable is connected to the brown/white which goes to ammeter and light switch, then disconnect the brown/white from ammeter and switch and  a test with engine running should show the about same voltage at disconnected end of brown/white end as it does at the red cable.

If not then logically the cable or connection with the red is faulty.

Looks like I have found the issue. Brown and white wire connects into a double connection. 14 volts in 12.2 out. Badly corroded so much so I cannot disconnect the bullet connections. B******s all this for a crappy connection.

[BSA500]

Just shoot me now and save me from this. So changed the connections. No charge-what??. Checked d&f together 20+ volts. Connected up the reg checked the output at A(Brown wire) and got 3-4 volts sometimes jumping up in value to 10 volts(as the engine slowed strangely). Now I know the reg is good and last night it was giving 14 volts rising smoothly with revs. What happened. Checking the wiring and its a mess so I am stripping it off and repairing it.
 Odd thing is the reg output was wired to the front brake switch so I am not sure how it even worked(and it did for many many years). I am at a loss, I cleaned up all the earths,checked the dynamo earth. I tested the reg in isolation so regardless of wiring issues it should still work. Arrrrrrrrrrrggggggggggggggggghhhhhhhhhhhhhhhhhhhhhhhhhhhh.(I would like to say that helped but it didn't)

[KiwiGF]

Maybe try getting the Dynamo to power a headlight bulb? By putting 12v through the field, and a 12v bulb on armature terminal. It's possible for a Dynamo to give volts on test, but not current. It would also be a good idea to check the polarity of the Dynamo as well, given all you've been through it could have got switched over! (By an inadvertent "flashing")

Possibly do the same test (with a bulb) with the brown wire off the reg and with the reg otherwise fully connected into the circuit, digital volt meters can give odd readings when the supply being measured it's not steady, a bulb is a more reliable test.

[BSA500]

Maybe try getting the Dynamo to power a headlight bulb? By putting 12v through the field, and a 12v bulb on armature terminal. It's possible for a Dynamo to give volts on test, but not current. It would also be a good idea to check the polarity of the Dynamo as well, given all you've been through it could have got switched over! (By an inadvertent "flashing")

Possibly do the same test (with a bulb) with the brown wire off the reg and with the reg otherwise fully connected into the circuit, digital volt meters can give odd readings when the supply being measured it's not steady, a bulb is a more reliable test.

When I test the regulator it is not connected to the loom /power so the field is not juiced. The only facts I know about this whole car crash is the charging was working the next day it wasn't. The dynamo gives 20+ volts when joining D&F with no reg connected. It was rebuilt in Nov by Andy at Priory mags so I have no doubts about that side of things. Its the 12 volt armature which has been very stable. The only thing I have not done is run a separate earth for the reg so I will do that tonight. I am also going to pull out the loom and repair that and set it up as the diagram suggests it should be. I have added extra earths etc over the years and its a mess really.

[BSA500]

Right. Last night removed the loom to tidy it up/repair whatever. Before I did I wired a separate earth to the reg and the brown output to a meter. The reg showed output but it was bouncing all over the place 4 to 10 back to 4 up to 11 etc. Is this because its not wired to the battery/loom etc. I know the earth was good I know the dynamo is putting out a consistent 20+ volts on the meter. The reg is new I am at a loss. I will wait until I have rewired and test again but if that's the same where do I go next. Send the reg to Mike for him to test it ??.

[KiwiGF]

If it's a digital volt meter it may very well bounce around if the reg does not provide stable voltage (it probably doesn't but gives "bursts" of power but the makers would know more) you will be best to connect to a battery to do a meaningful test, as that will stabilise the charging voltage.

If the charging voltage is not stable an old style mechanical voltmeter will give nearer to an average voltage as it cannot react quickly and that would probably be meaningful, a digital meter which can react quickly will usually try to "follow" the voltage fluctuations and will "bounce around" as a consequence.

[BSA500]

If it's a digital volt meter it may very well bounce around if the reg does not provide stable voltage (it probably doesn't but gives "bursts" of power but the makers would know more) you will be best to connect to a battery to do a meaningful test, as that will stabilise the charging voltage.

If the charging voltage is not stable an old style mechanical voltmeter will give nearer to an average voltage as it cannot react quickly and that would probably be meaningful, a digital meter which can react quickly will usually try to "follow" the voltage fluctuations and will "bounce around" as a consequence.

Thanks that could be the issue. I think I should make sure the wiring is sorted, check over the dynamo(polarity etc paranoid check  ) and then start again.

[BSA500]

Did a polarity check last night and everything is as it should be.

[Greybeard]

...a digital meter which can react quickly will usually try to "follow" the voltage fluctuations and will "bounce around" as a consequence...

This had me pondering about connecting a suitable capacitor across the meter to damp fluctuations. What do you electro-blokes think about that?

[Bsareg]

You would also need a resistor to discharge the capacitor or it would just show peak voltage as the internal resistance of a digital meter is several million ohms and could take some minutes to show the correct reading. A side light bulb in parallel with the meter leads and capacitor would be OK.

[BSA500]

Hoo-bloody-ray. She is now charging. Rebuilt the loom got rid of surplus wires and dodgy connections and she now charges as she should. Prob the old reg is fine but I don't care anymore 

[Slippery Sam]

whoop whoop
Well done - I bet you let out a decent sigh of relief when you saw it working correctly.
Good perseverance - it paid off even if it were a tad frustrating for you at times.
These kind of things can get really technical and go down all sorts of roads, it's a bit like navigating and choosing the right direction.  In the end it so often turns out to be a dodgy wire or duff connector hidden away somewhere and not the highly technical stuff.
Good job and another good thread working through the logic and trials and tribulations.
Stick in!
Raymond.

[BSA500]

whoop whoop
Well done - I bet you let out a decent sigh of relief when you saw it working correctly.
Good perseverance - it paid off even if it were a tad frustrating for you at times.
These kind of things can get really technical and go down all sorts of roads, it's a bit like navigating and choosing the right direction.  In the end it so often turns out to be a dodgy wire or duff connector hidden away somewhere and not the highly technical stuff.
Good job and another good thread working through the logic and trials and tribulations.
Stick in!
Raymond.

Thanks. Partly because I am bloody minded I worked my way through it. Partly also there are no people/places locally that could understand, what is actually a very simple wiring set up, enough to be able to help. If it can't be plugged into a computer they are lost. I'm not putting them down it's just progress. Also problem solving like this takes time and time is money  . Hopefully a full summer of riding awaits then come winter the gearbox will get some attention(I would like to work on the car project now)

[beezermacc]

Delighted you got it sorted. This is how experts are made!

[BSA500]

I think I now actually understand the wiring on this bike. It went very well yesterday,charging spot on. Pity about the leaky rockerbox, a little oil goes a long way