Battery not charging

[Chris Sealy]

You appear to have the standard Lucas C35SD dynamo, so no worries there. Don't rush into dynamo removal until after proving it to be faulty. This is normally possible to do with it in situ.
You say that the dynamo is putting out a few volts, where did you measure this?
In order to test the dynamo properly, it must be disconnected from the regulator.
Remove the rear end cover, then disconnect the two wires. See my previous post. Insulate the two wires to avoid shorting them.
Connect the dynamo terminals together with a link wire, as shown in the picture. Connect your voltmeter between this link wire and the body of the dynamo. Start the engine and slowly raise the engine speed. The meter should show a reading around 1 volt which ramps up rapidly as the engine speed increases. If you get 10 volts or more at a fast idle the dynamo is working. Do not go above 12 volts because the old field coils may be damaged.
Cheers, Chris.

[BruceWatts]

I now realise that you are able to "Flash" the Dyno. This will be my first port of call. Seems like a simple task as long as I can get the chrome end cover off the unit. I have tried that already without success, but maybe it needs some KY jelly and a waggle !!!
My bike is fitted with a Watsonian side car, which makes access to the Dyno even more difficult!
I am not sure what you mean by a control box?
Chrs
Bruce

[simon.holyfield]

The control box is the widget that regulates the dynamo output. It's a little black box under the seat.

[will_curry]

. . . or an alloy box as used by the JG regulator which has graced my Mk 1 for over 40 years.

[ian williams]

hi Bruce ;
if youve got an original lucas MCR2 type voltage regulator same as i did on my NH then that will most likely be the problem , they unfortunately dont last forever .
mine stopped working , i got it going again for a short time but it packed up again , i then fitted an indian made copy but that didnt last more than about 30minutes .
i changed that for a wassell solid state regulator but whilst it did work my battery would go flat after a few days due to the residual current drain of the wassell regulator , so i took that out and fitted an AO services v-reg which worked and the battery stays charged up almost endlessly , without me needing to charge it in 2 years .

this is a good link below to see how you can fit the AO v-reg into the old lucas box , i broke my regulator down into pieces so i could use the alloy bracket in it to mount the AO regulator to it but you can fit it how you like as theres loads of room in there .

https://ariel-square-four.blogspot.com/ ... lator.html

hope you get sorted .
ian

[Heiko.Hecht]

Another possible cause of the problem is that the collector may be contaminated by an oxide layer and needs to be cleaned.

Heiko

[BruceWatts]

Hi Guys,
Despite all of my best efforts, the problem still exists.
I have now embarked on a journey to remove the dynamo and have got to a point of some concern.
Having removed all sprockets, plates and bolts, how do I get the whole assembly out of the engine. Do I need to remove anything else. eg distributor, bushes, or something on the front of the dynamo?
I assume that when safe to do so, something needs to be pushed or pulled or knocked out !! Here is my real concern, what and how?
I suppose then I will be asking how to get it back in again !!

[paul.jameson]

Bruce,
The lack of charge may be a blessing in disguise. Your engine internals are coated with gunge deposited there by non-detergent oils over the years. The detergent oil you are now using is washing the gunge off - as can be seen where you have wiped the end of the dynamo with a cloth. The gunge will collect in the crankshaft sludge traps and eventually block the oilway to one of your big ends - usually No 3. When this happens, the big end seizes, the con-rod breaks and exits through the crankcases, leaving you with a wrecked engine. From starting to use detergent oil, you have approximately 500 miles before the sludge traps are full and the engine explodes. That figure comes from the Healey brothers who saw very many Square Four engines wrecked in this way when detergent oils first appeared in the 1970s.

You need the engine stripped down and the sludge traps cleaned out before it is started again. At the same time you will end up doing more to the engine - such as replacing the original oil pump currently fitted with a modern Morgo pump.

None of this is welcome news - but you are not the first to receive such advice and it is better than a blown up engine.

[Chris Sealy]

Remove the distributor, and the nut to the right of the dynamo shaft.

[BruceWatts]

Hi Chris,
So after giving the unit a good clean, it was indeed caked in crap and oil due to a old faulty oil seal, I conducted your resistance check.
The upper measurement was 2,5 ohms but I could not get a resistance figure at all from the lower.
I have attached a pic of how I have connected the wires, one of which earths to the alloy body. Is that correct?
Thks
Bruce