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2024-06-11, 20:02:05
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Magneto to HT lead connection

Started by dalgrae, 17 Jul 2014 at 06:02

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dalgrae

As I am about to refit my refurbed mag/dyno can someone please confirm this ,the HT lead is at present connected to a thin brass washer with the wires splayed out on one side which is then screwed into the magneto ,my question is should the lead to brass washer connection be soldered

regards  Colin

eddie

Colin,
         It makes no difference - the screwed collar of the HT pickup presses against the brass washer which in turn clamps the splayed end of wire against the end of the centre post.

     Eddie.

dalgrae

Thanks for your reply

Regards  Colin

Doug

Colin,

As Eddie says, it does not matter. The voltages are so high, the spark will easily bridge any minute gaps (if there are any). Soldering does keep it neat and together, but if you do not have a soldering iron to do the task it is nothing to worry over. The gap at the spark plug sets the minimum resistance of the circuit. Once the potential is high enough to jump the gap there, it will bridge anywhere else of a lesser gap.

-Doug

eddie

I leave the washers unsoldered on road going machines - it's much easier to just pare back the insulation and remake the lead should you have problems on the road. Much more difficult to remove the soldering in order to remake the joint when stuck at the roadside with only a minimal toolkit. Having said that, I do solder the leads on my sprint bike to ensure reliability - but we do have spare leads, and even magnetos with us in the event of problems occurring.

      Eddie.

dalgrae

Thanks again for the advice ,I saw my magneto on test when I picked it up this week and the spark was jumping a 5mm gap at tickover so hopefully I can look forward to many trouble free miles

Regards  Colin

eddie

Colin,
         Please do not try to repeat the practice of getting the mag to produce a long spark - you could end up ruining the windings if the spark should jump across them, rather than jumping the gap at the end of the HT lead. BTH magnetos have screws that project into the 'V' of the slip ring that limit the length of spark generated, thus preventing too high a voltage from being produced within the windings. Unfortunately, Lucas magnetos don't usually have this refinement.

  Eddie.