Author Topic: Headlamp Shell Earthing  (Read 155 times)

Offline Nourish

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Headlamp Shell Earthing
« on: 17.02. 2020 15:01 »
Why does (usually) a headlamp shell have a earthing point?

Online bsa-bill

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Re: Headlamp Shell Earthing
« Reply #1 on: 17.02. 2020 16:58 »
Possibly --- because the earth is normally via the bike frame meaning it has to track through grease filled bearings (which it does fairly effectively) but many (me included) like to run an earth wire front to back for a more reliable earth
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline A10 JWO

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Re: Headlamp Shell Earthing
« Reply #2 on: 17.02. 2020 18:10 »
Even the Japanese cousins do that and Italian Scooters.

Online Swarfcut

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Re: Headlamp Shell Earthing
« Reply #3 on: 17.02. 2020 18:20 »
    Could be a one size fits all, and Old Joe Lucas found it cheaper to make all shells electrically the same.  There would be need for some guaranteed earth return for pilot bulbs on rubber mounted speedos, rather than the grease filled cable, so having some central earthing point makes sense, and  an Earth connection from lampholder to headlamp shell and then to frame via grease filled headstock bearings was the way it was done.  Your own earth wire is a worthwhile improvement, as noted.

 Swarfy

Offline Triton Thrasher

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Re: Headlamp Shell Earthing
« Reply #4 on: 17.02. 2020 22:35 »
So any electrical components mounted in the headlight can be earthed to the shell.

Obviously, we connect the shell to the battery return pole with an actual wire.

Online Slymo

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Re: Headlamp Shell Earthing
« Reply #5 on: 18.02. 2020 06:00 »
I think people who have an issue with 6v systems have often failed to properly earth the various parts of the bike. I generally make my own looms and have a good substanial earth wire running to all points from tail to head and inbetween. Its very important at the headlight as failure to do so can result in the spark erosion of the headrace bearings.
NZ