BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: tdc on 20 Mar, 2024, 15:21

Title: 68 Lightining
Post by: tdc on 20 Mar, 2024, 15:21
Not being familiar with 12v. + earth ignition system. Which ammeter terminal does the fused - lead from the battery go to  ?  Thanks .
Title: Re: 68 Lightining
Post by: Steve.S on 20 Mar, 2024, 17:44
Ammeter terminals are not usually marked. So just connect it up and if the ammeter shows a charge when the headlight is switched on, swap the wires over.
Title: Re: 68 Lightining
Post by: tdc on 20 Mar, 2024, 20:35
Thank's I have an original wiring loom and am starting from scratch so I need to know from the battery .On a 6v diagram the ammeter discharged to the left when viewed from above the ammeter itself being illustrated -and + as I am sure that you are aware .So as I have little awareness of 12v electrics I need a base line to work from the battery seems a good place to start  ?
Title: Re: 68 Lightining
Post by: Allan G on 21 Mar, 2024, 08:02
From memory it's battery to the + side of the ammeter.

As Steve said, an ammeter isn't polarity sensitive, but the needle will flick towards electron flow. Ie. If your engine isn't running and you put the lights on, electron flow would go from the positive side of the ammeter to the negative side as the negative side is the load and the charging side.

When the bike is running at sufficient revs, the battery charges, so more electrons to the battery so from the negative side of the ammeter to the positive.

The ammeter will work either way, but it's common sense that you want it to show as charging (+) when the battery is being charged.
Title: Re: 68 Lightining
Post by: DAVE BRADY on 21 Mar, 2024, 08:26
Hi,

Page G27 in the manual shows in fig.G19, the battery and horn connection to the righthand side of the ammeter and everything else from the lefthand side.

Dave.
Title: Re: 68 Lightining
Post by: tdc on 21 Mar, 2024, 11:10
Thanks for replies most helpful .