Ammeter

[mikeydpippin]

Not found this one in the search.
I have fitted a brand new Jampot spares 6v battery correct for my G3.
Everything works fine,all electrics superb!!!
Except the Ammeter,
The bike is wired Positive earth and i have the + of the battery connected to the earth.
The ammeter shows 1/8th positive with all electrics OFF,but when i turn the lights on Pilot lights flick the Ammeter to 1/4 positive and Headlights flick the Ammeter to 3/4 positive.
This cant be right,i have switched battery connections and the same happens in reverse ie. up to 3/4 negative.
I have checked and double checked all wires and earths.
This happens with the old regulator and with the new DVR2 i have just fitted, before this the battery kept dying,so presumed regulator fault.
Any ideas?.
Oh yeah Dynamo has been profesionally refurbedEdited by - mikeydpippin on 04 Aug 2010 8:23:08 PM

[Don Madden]

For the direction of the needle, forget the markings & connect so that it shows (-) when the lights are on. Even genuine Lucas ammeters often park off center so a small deviation should be ignored. Cheers, Don.

[mikeydpippin]

Thanks Don,I have found a recent thread by Laxy,
http://www.ajs-matchless.com/topic.asp? ... Title=Help
I have flashed D and F terminals and the ammeter now shows a max positive of 1/8th and only showing 3/4 positive on full beam so somethings changed.
When you say connect to show (-) when the lights are ON do you mean change the ammeter connections over or the battery connections,
Sorry to be a bit "green".

[itma]

change the ammeter connections over then it will show -

[mikeydpippin]

Sorted,
I have swopped the terminals on the Ammeter and Bingo!!
The ammeter now shows 0 with nothing switched ON goes to -1/8 with headlights on and - 3/4 with full beam on,
Thanks Don,i knew the answer was in there somewhere.
My ammeter has no markings on either terminal,so didnt know which connection were correct.
I do now!!!
Sorry Ken,You must have posted same time as me your right.
Again!!!Edited by - mikeydpippin on 04 Aug 2010 10:47:07 PM

[DWS]

Why were some bikes negative earth and some positive? Was it a year/model thing? Sorry electrics are not my strong point

[Eric]

I don't know if applied to bikes but it was supposedly discovered that the traditional way of connecting up a car meant that it was trying to electroplate itself to the ground and when monocoque bodies became the normal thing this became an added problem as it increased the rate of corrosion. This meant that Vauxhalls could be in holes within just 18 months, so they changed it round in cars, then a Vauxhall could manage 20 months. Perhaps the same applied to bikes or it was just to keep things the same?

It may also have or alternatively be something to do with trying to reduce the amount of corrosion formed around the battery terminals.

[Groily]

Reckon that's about right Eric, (especially the shelf life of a Vauxhall of the period . . . gawd they rotted in front of our eyes). But probably lousy steel and lack of proper paint treatment as much as anything. Nowadays cars go the scrapper because some daftly expensive little bit of kit has packed up - while the bodies sit there in indestructible piles.
Interesting that so many continental motos were always negative earth, even back then . . .
But I keep my old bikes on positive so I don't get muddled up between them after a glass of anything stronger than water . . .

[DWS]

My Matchless workshop manual wiring diagram shows my 1950 model G3L as negative earth, and that's how it is wired up. Did Matchless/AJS swop these around from time to time?

[1608]

I always believed that Brit vehicles changed from Pos to Neg earth in keeping with other and esp Euro countries. I recall having to fit polarity convertors whenever I wanted to fit a stereo which came with me from car to car, because they were not standard fitments then.Edited by - 1608 on 05 Aug 2010 11:44:10 AM