The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Stephen Foster on 08.09. 2012 07:51

Title: Headlamp Wiring query ?
Post by: Stephen Foster on 08.09. 2012 07:51
Apologise upfront if I appear to need leading by the nose recently but Im fitting a new harness to the "Flash", (S/A with cowl) . 1955/56 .

Trying to work out if the wires to parking light , speedo light ,dipeswitch, kill button, etc should actually run through the headlamp bowl (prefered for weather proofing) or
ought to run behind the bowl ?

Also Im unsure how the speedo bulb is to be earthed ?

Im no electrician but am doing My best in unfamiliar territory .

Thanks in advance ,

Steve ...
Title: Re: Headlamp Wiring query ?
Post by: duTch on 08.09. 2012 10:16
Hiya Steve,

             I reckon the bulb should work no matter which way it's wired, but also I'd've thought it'd be self evident, if not, depends how politically correct you want to be, just make it work, if you have a fuse in the system you can't blow up the world..??..maybe???
 cheers, have a nice day , duTch
Title: Re: Headlamp Wiring query ?
Post by: a101960 on 08.09. 2012 11:36
Stephen,

The wiring goes inside the headlamp bowl, and the speedo lamp is earthed through the speedo casing ( see diagram below). From 1956 on a combined dip switch and horn button was fitted to the left hand side of the handle bar. The "kill" button was fixed to the centre of the handle bar behind the steering damper knob. The combined dip/horn switch would have been a ducon. Incidentally, the diagram that I have posted is for a 1955 model which had separate horn, kill, and dip switches. The BSA part number for the ducon is 19-100. Up until 1955 the pilot lamp was the underslung type from 1956 on the pilot lamp was mounted in the reflector. The correct kill switch would have been the Lucas type shown here, but there is no part number listed in the BSA parts list.

John

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Title: Re: Headlamp Wiring query ?
Post by: KiwiGF on 08.09. 2012 12:02
Coincidence....I'm finishing a home made loom at the moment and when the speedo light did not work today I realized it's rubber mounted - DOH! Everything else worked fine.

So the speedo casing needs to have separate wire to earth it.

I've been wiring everything back to one earth point near the battery so this a pain to find out now!

I suspect I have the wrong dip switch by the look of it, its got a plastic horn button. My  kill switch also has a plastic button, I suppose these switches are hard to get ?
Title: Re: Headlamp Wiring query ?
Post by: a101960 on 08.09. 2012 12:51
Quote
I suppose these switches are hard to get ?

KiwiGF

Absolutely not! Common as anything all over the internet. Here are just two randomly picked sellers.

Ducon switch
http://www.ebay.co.uk/itm/BSA-NORTON-REPLICA-WIPAC-DUCON-DIP-HORN-SWITCH-/221105337929?pt=UK_Motorcycle_Parts&hash=item337ae7b649

Lucas Kill switch
http://www.ebay.co.uk/itm/LUCAS-SWITCH-REPLICA-HORN-KILL-/290738516279?pt=UK_Motorcycle_Parts&hash=item43b15db137

I assume that all the chrono speedos will be fitted with mounting studs so fixing an earth strap would be no problem. The original wiring diagrams are not very good at explaining the details such as that. The other problem is that many repro wiring harnesses have cable some colours that are different to those shown in the diagrams. That is not to say thay are wrong because the colours do tend to change from year to year. The problem is that to save on costs all harnesses for an A10 or A7 irespective of  the model year are often generic harnesses made up from a specific year diagram and do not reflect or include the sometimes odd cable colour changes that occured.

John
Title: Re: Headlamp Wiring query ?
Post by: Stephen Foster on 08.09. 2012 16:27
Thanks all for the input ..Im very grateful indeed !
I think Ive cracked it .
I have the correct , original switches fitted , they differ from the "Ducon" .

I wound a wire around the speedo bulb holder , soldered it into a neat ring & ran this to the earth connector built into the headlamp bowl , this being necessary as the speedo is rubber mounted & therefore insulated .

Assume there must be a simpler set up but it beat Me !

I am using a bought in harness with correct wire colours & braided sheething .
It has taken Me 2 days to fit as Ive worked slowly & carefully .

The machine is taking shape very nisely now & I am indebted to this Forum for the largemount of advice Ive received along the way especially from "Brian" , "Muskrat" , "Chaterlea", etc .

"A101960" , thanks for taking time to post those pictures to help Me .

Regards,

Steve...
Title: Re: Headlamp Wiring query ?
Post by: Stephen Foster on 08.09. 2012 16:52
Ive just been given an inline fuse holder & am unsure where I ought to fit this to best advantage ?
Hope Someone may be able tp help Me please ?

Regards,
Steve...
Title: Re: Headlamp Wiring query ?
Post by: rocket111 on 08.09. 2012 20:30
Yes the speedo is rubber mounted but the earth is very sucessfully provided by the speedo cable which isnt  ;)
Title: Re: Headlamp Wiring query ?
Post by: trevinoz on 08.09. 2012 22:05
A couple of comments,
                                   The wiring and connections are all in the cowl, not the bucket.
The hole in the bucket for the wiring is not big enough for all wiring to pass through.
The A7/10 never used a Ducon switch, post 1960 the Tricon switch was used.
For 1955 the dipper switch was the bakelite type mounted on the left hand lever pad.
The horn button was the same as the cut-out button mounted on the right hand lever pad.
From 1956 the combined dipper horn switch was used. This is the mushroom head Lucas type.

  Trev.
Title: Re: Headlamp Wiring query ?
Post by: chaterlea25 on 09.09. 2012 20:29
Hi Steve,
Fit the fuse as near to the battery as possible, that way theres less "unfused" wire to worry about  *eek*
It does not matter if its fitted on the live or earth side of the battery !!
On occasion I have just replaced the battery to frame wire with the fuse unit , most inline fuses now seem to be the blade type which come with a loop of wire attached, similar to this
http://www.ebay.co.uk/itm/In-Line-standard-waterproof-Blade-Fuse-Holder-fuses-30a-30amp-kit-car-boat-bike-/300640459432?pt=UK_In_Car_Technology&hash=item45ff915aa8

Regards
John
Title: Re: Headlamp Wiring query ?
Post by: KiwiGF on 10.09. 2012 01:46
So, just to be certain, the only wires that go into the headlight bowl (bucket?) are the wires leading to the headlight and pilot bulbs?

And all the other wires/connectors (to/from dip switch, main lighting switch, ammeter etc) are all "sandwiched" between the nacelle and headlight bowl?

As the other post says the hole in the headlight bowl grommet is only about 3/8 so not many wires can be fitted through it.


Title: Re: Headlamp Wiring query ?
Post by: trevinoz on 10.09. 2012 05:21
That would be right, Kiwi.
An earth wire as well is handy.
The rest aren't really "sandwiched" as there is plenty of room.

Trev.
Title: Re: Headlamp Wiring query ?
Post by: Stephen Foster on 10.09. 2012 06:27
Hi Steve,
Fit the fuse as near to the battery as possible, that way theres less "unfused" wire to worry about  *eek*
It does not matter if its fitted on the live or earth side of the battery !!
On occasion I have just replaced the battery to frame wire with the fuse unit , most inline fuses now seem to be the blade type which come with a loop of wire attached, similar to this
http://www.ebay.co.uk/itm/In-Line-standard-waterproof-Blade-Fuse-Holder-fuses-30a-30amp-kit-car-boat-bike-/300640459432?pt=UK_In_Car_Technology&hash=item45ff915aa8

Regards
John


Thanks John !
Assume the 30Amp fuse to be correct for My purpose ?

Steve ..
Title: Re: Headlamp Wiring query ?
Post by: duTch on 10.09. 2012 09:35
30 amps is fairly big, given that the genny output is ~10, and the standard load is less, I reckon 15  at the most, maybe even 10'd be orright, as a starter? If that blows, there's something needs be addressed?

Cheers duTch

      Nb- and if you're running 12V, halve amps?
 Could be wrong..?
Title: Re: Headlamp Wiring query ?
Post by: KiwiGF on 10.09. 2012 10:26
Thanks Trev, it's not a standard loom I might as well route it close to oem.
Title: Re: Headlamp Wiring query ?
Post by: BSA_54A10 on 12.09. 2012 10:14
Also consider fusing both sides of the battery plus the feed wire from the regulator to the ammeter .
The reason for this is if you get a short in the headlamp while the bike is running the dynamo will continue to pump in power till either it dies or your wiring burns.