[72degrees]

Many thanks for more great links. nearly ready to start testing. Had to get it starting easily and idling well first.

[Greybeard]

Good morning. I can confirm that the late pre-war bikes were wired up as negative earth - my 36/37 Lion was. I changed mine over to positive earth simply to match all the other bikes so that I can if necessary swap batteries around using a simple connector. Ive grown too mean to maintain over a dozen 6v batteries now
I also fitted a DVR2 regulator though if your control box is still working correctly it may as well stay.
If youve not come across the site, try this one for a very straight forward explanation of dynamo systems - his book is excellent too and well worth getting -

https://www.matchlessclueless.com/

https://www.amazon.co.uk/Classic-Motorcycle-Electrics-Manual-James/dp/1847979955

Steve

[phutton]

Looking at the wiring diagrams in the Pitmans book, the system is Negative earth. However, as Graham says, the system could have been messed with over many years, so a thorough check will be necessary. (mine doesn't work either!)

P.

[72degrees]

A really useful link. Thanks having run Moto Morinis for years I'm used to having to perform electrical tests  , but it's decades since I had anything with a dynamo.

[shorrog]

I guess the thing is that as it is possible to change the bikes polarity it does not really matter how it left the factory if in the mean time someone has modified the bike to the more modern negative earth. If you wanted to put some LED lights on the bike then the negative earth gives you more choice.
The first thing to do is to check the dynamo the Vintage Motorcyclist's Workshop has a good description of how to check.
I also found this on the ariel owners club http://forum.arielownersmcc.co.uk/viewtopic.php?t=189 which also looks useful.
Graham

[72degrees]

My first technical question.

The charging system on my recently acquired 23S does not function. It has been rewired and a new modern battery fitted (not by me). The battery has been connected as NEGATIVE earth. Would the machine originally have been positive earth? I'm aware that conversion is possible, but could this explain no charging. I will get out the multimeter and check dynamo output, but that will have to wait while I sort the flooding carb out. I should have had a quick poke about while I did have it running for a while with the fuel off.