Author Topic: new wiring loom  (Read 362 times)

Offline Swarfcut

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Re: new wiring loom
« Reply #15 on: 07.07. 2020 13:34 »
How you proceed depends on what's best for you.  As an observation, an existing commercially available loom will cope with 12 volts. The current flowing remains more or less the same whether the system is 6 or 12 volts. The higher power required by higher wattage bulbs is compensated for by the higher operating voltage, and 12 volts gives a little more choice in the way of bulbs, horns and electrical accessories.

   The relative cost differential of 6 volt and 12 volt armatures and field coils is marginal, and if the existing dynamo is truly finished, then well worth swapping for the higher output parts.

 The usual practice of wiring brake and horn directly prevents the ammeter being subjected to irregular high currents, more as a way of preserving its longevity, and also  if wired through the ammeter a failure would render these "safety critical" components inoperative.

 The Lucas regulator terminal block always raise a smile..... depending on model the letters are D.E.A.F or F.A.D.E     Says all you need to know about Lucas Electrics......

 If making your own loom, add a nice big earth wire from Forks to frame/battery earth. Normal earth return from the headlamp and forks is through the nicely greased headstock bearings, and adding an extra earth often improves an otherwise weak headlight output. Never been a fan of magneto cooking, preferring airing cupboard or top of the wardrobe storage

 Swarfy.

 
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Online Rex

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Re: new wiring loom
« Reply #16 on: 07.07. 2020 16:18 »
Regarding earth paths, there's a good earth connection from the handlebars to earth via the clutch cable, and depending on the design, possibly the throttle cable, choke or even decompressor too.
A separate earth cable run to the rear light is also sensible.
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Offline Swarfcut

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Re: new wiring loom
« Reply #17 on: 07.07. 2020 18:20 »
Rex   Yes, greased cables do conduct.   Years ago, swapped the engine unit on an original Mini.  All was good, started, ran fine, but the choke knob was stuck.   Realised in our haste to finish, muggins had forgoton to re attach the chassis/engine earth strap and the starter current had found its way home down the choke cable and welded the inner and outers together. These days I always add an extra direct earth from the battery to the block on old time classics, to give the starter circuit a better chance.

 Swarfy
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Offline BSA_54A10

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Re: new wiring loom
« Reply #18 on: 08.07. 2020 06:41 »
Rex   Yes, greased cables do conduct.   Years ago, swapped the engine unit on an original Mini.  All was good, started, ran fine, but the choke knob was stuck.   Realised in our haste to finish, muggins had forgoton to re attach the chassis/engine earth strap and the starter current had found its way home down the choke cable and welded the inner and outers together. These days I always add an extra direct earth from the battery to the block on old time classics, to give the starter circuit a better chance.

 Swarfy

Just ask any one who has a 71 on model with that idiot front brake switch.
Yes greased cables, connected to rubber mounted handlebars and a brake plate that is grounded through a greasy steering bearing.
They conduct really well.
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Bike Beesa
Trevor

Online Rex

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Re: new wiring loom
« Reply #19 on: 08.07. 2020 10:03 »
"Greased" has no bearing on the issue. The path would be, handlebar, lever clamp, lever, cable nipple top end, cable, lower end cable nipple, clutch mechanism etc.
The '71 on OIFs had rubber-mounted 'bars and no hard-wired earth connections to the Dan Dare switchgear that I can recall, yet the horn worked just fine.
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