AJS & Matchless Owners Club

Just a quick and probably daft question, why is my battery connected with the black wire to positive and red to negative?

I'm about to charge it up for the first time and presumably I connect the charger red to positive and black to negative as normal?

Thanks

always check the battery markings , don't assume that the wiring is correctly coloured
All batteries are marked + and -

I was very surprised to see how it was wired so I looked carefully at the battery markings, I suppose I'll just give it a charge and put it back on the same as it was, after all it ran OK!

Thanks

when you connect it up turn lights on if the ammeter shows discharge then it is connected the same way as before, if charge then it is the wrong way round. Possible someone has changed from positive earth to negative earth to allow installation of modern electrical regulator box etc most of which work on negative earth. Lazy not to change the wire colours but quite possible if bike new to you, amazing how some people do a bodge of course I am never one of those (eh Sam)

Wire the bike as it should be, charge the battery battery + to charger + reguardless of + being earth on your bike, which is probably correct, check the wiring diagram for your bike

I noticed last night that if I wire the battery 'correctly' (+ to red and - to black) then turn the lights on, it is showing a charge and not a discharge. I stumbled on this by accident by getting it wrong when trying to connect it the wrong way round and accidentally getting it 'right'. If you see what I mean. But thanks for confirming that this is a valid observation.

It has a Lucas RB108 regulator fitted.

I've only had the bike for a week so I'm just going around it trying to get to know it. I'll check the wiring more extensively when I have a clue what I'm loooking at.

Incidentally, can you tell me which bolt is the drain-plug bolt for the gearbox? Is it the flat headed bolt with a fibre washer under it (lower and closer to the centre of the bike) or the domed bolt closer to the kickstart?

Matthew, If you have an AMC Gearbox the domed bolt is the housing for the indexing spring and plunger for the cam-plate, have you visited the archives and equipped yourself with manuals and parts lists?

If your engine was not running then the lights should show a discharge when turned on (i.e. power is being taken from the battery).

The wiring diagrams for the dynamo models seem to show that Black goes to earth - so connected to the + terminal.

you haven't by any chance charged a totally flat battery the wrong way have you? It is possible to reverse the polarity so use a multimeter to check that your battery is reading correctly for the terminal markings.

I was recently sold a new battery with the terminals wrongly marked. Caused a bit of head scratching at first, but a multi-meter confirmed which terminal was which and no damage done.