Battery or earthing problem?

[wilko]

Just walk away and go back to it later! That's how lots of my gennys start working.Have you motored it to see which way the field wires are connected? The sparkie might have wired them for running in the opposite direction.

[trevinoz]

Hubie,
            As Wilko said, it may be connected incorrectly internally.
Take it out and motor it.
If you don't know , connect D & F together and connect hot wire to them with earth to body.
The generator should run in the driven rotation, in your case anti-clock or left hand if you will, viewed from the drive end.
If this is the problem, just swap the field wires around and test again.
Trev.

[Hubie]

Have swapped the wires around and back again with no difference in the result.  Getting .2 to .24 volts at idle.  Might have to take it back where it came from.  Brushes are rather worn but still making contact so I'm not sure where to go from here.

Out on the road the 24 tooth engine sprocket seems fine, struggles a bit at 60mph which it did before the change.  Might have to get it looked at.

Cheers,

Dave.

[trevinoz]

Dave,
          Have you gone through the test procedures, i.e. disconnecting generator and bridging D & F and seeing what you get?
The first thing is to ensure that it motors in the correct direction with the correct polarity.
Did you flash the field after you swapped the connections?
If the generator is still in the bike, you have to flash the field if you change the field connections.
Regarding the 24 tooth sprocket, you are over geared to buggery.
I am one of those strange blokes who believes that the designers of the bike knew what they were doing regarding gearing.
               Trev.

[Hubie]

Okay,

I removed the timing cover and disconnected the dynamo chain tonight and connected the f and d terminals, put some voltage across it and earthed the body.  The dynamo runs, so now where do I go????

Cheers,

Hubie.

[bsa-bill]

 a friend had this trouble, turned out was polarised wrong way by repairer.

might help the dynamo experts here ( not me ) if you could say which way it ran - clockwise or anti.

Reading your post again I can't see anywhere that you have the bike wired positive earth as it probably should be, sorry if this is an obvious point but pays sometimes to get all the boxes ticked before giving advise ( boxes ticked - not bad vernacular for n old F*** eh )

All the best _ Bill

[Brian]

I take it this gen is off the bike in your profile photo Hubie, if that is the case then it is most likely positive earth. That being the case you need to connect the battery negative to the wire bridging the F and D terminals of the gen and then connect the positive of the battery to the body of the gen. This should make the gen spin in the correct direction, anti clockwise looking at the drive end. If not reverse the wires that are inside the gen and go to the F and D terminals and try again. Once you have got the gen to spin the correct way then either put the chain back on and check it for output again or spin it the correct way with a electric drill and check it.

Make sure your bike is positive earth before trying this, trace the wire from the positive terminal of your battery to make sure it goes to the frame (earth).

If by any chance your bike has been wired with a negative earth then you need to do exactly the opposite of what I have said.

Hope this makes sense.

[Hubie]

It's a positive earth machine for sure.  Nice and original!

[MG]

So does it spin in the right direction then?

[Hubie]

Have re flashed the dyno as per Brian's description and I get 0.2 to 0.4 volts coming out of it.

[muskrat]

Dave, did you take the chain off to see the dyno motor? This is important as you can flash it till the cows come home but if it doesn't motor it wont charge.
cheers

[MG]

Okay,

I removed the timing cover and disconnected the dynamo chain tonight and connected the f and d terminals, put some voltage across it and earthed the body.  The dynamo runs, so now where do I go?

Cheers,

Hubie.

I assume he did so, muskrat.

Still Dave doesn't want to tell us which way 'round it ran.  
Maybe the dynamo guy got the field coil connections wrong, who knows.

[muskrat]

Sorry Dave, I didn't read back far enough. You got me baffled. I recently had electrical problems. The brush plate broke and melted the armature. Rebuilt dynamo and then cooked 2 batteries.Turned out it cooked the DVR2 as well.
Not much fun is it?
Cheers

[Hubie]

I did take the chain off.  I assume that the dyno would not have near enough power in it to turn the motor over!
I am wondering since the dyno ran that the brushes may be stuffed...

[bsa-bill]

it needs the brushes to motor Dave, so they must be OK, you still need to let us know in which direction it rotated when you had it motoring?