Author Topic: Lucus 8H Horn advice please  (Read 824 times)

Offline Billybream

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Lucus 8H Horn advice please
« on: 13.06. 2012 08:57 »
 Just rewiring my 1960 Super Rocket after complete renovation, horn will not work, tried small adjustments by both screws but no action, construction is crimped, can I strip to investigate further, any tips please. Mine is 12 v version horn running on 6 v system, with date stamp of 466, so prehaps not the original.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline BSA_54A10

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Re: Lucus 8H Horn advice please
« Reply #1 on: 13.06. 2012 11:37 »
You will not have much luck getting a 12 V horn to work in a 6 V harness.
It will draw near 20 amps which your system will have difficulty supplying and at best will make an anemic croak.
To add to that the extra current draw will burn the contacts in the switch & horn.
If you want it to "look right" leave it there & cut off the wires just inside the loom.
Fit a modern 6 V horn ( japanese trailie ) under the tank or behind the tool box where it can not be seen
Bike Beesa
Trevor

Online trevinoz

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Re: Lucus 8H Horn advice please
« Reply #2 on: 13.06. 2012 23:03 »
I don't think that a 12V horn will draw 20 amps as it has twice the resistance of a 6 unit.
However, you won't get much noise out of it if you get it working.
Mostly horns stop working after lying idle for some time because the points get a film of corrosion or oxidation which effectively raises the resistance or insulates the points.
The only cure is to clean the points and readjust the horn.
I have never dismantled an 8H, yet, but I think they are riveted together. I will check later.
Your 1960 bike probably should have an HF1441 horn, like Triumph and some AMC bikes had.
The 8H was fitted at some time but it is unclear when.
Best you find a 6V unit or do as Trevor suggests.

Trev.

Offline Billybream

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Re: Lucus 8H Horn advice please
« Reply #3 on: 15.06. 2012 07:22 »
Thanks for the advice, going to hide low cost replacement unit. Wiring now complete, all works ok, just await tank and guards from painter to complete my restoration.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline BSA_54A10

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Re: Lucus 8H Horn advice please
« Reply #4 on: 15.06. 2012 08:56 »
Quote
I don't think that a 12V horn will draw 20 amps as it has twice the resistance of a 6 unit.
*problem* Err year OK got that one a bit backwards.
Bike Beesa
Trevor

Offline duTch

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Re: Lucus 8H Horn advice please
« Reply #5 on: 15.06. 2012 09:38 »

Heya Billybream, And all, Here's a link to the guy in South Aus.,
 http://www.classicandvintagebulbs.com/

I had a look the other day for halogen bulbs and saw he does a 6v 100mm horn chrome grille all the stuff looks ok- $ 35au. I'm looking at doing one, it could be what you need.
 If I can post a pic I will but not looking promising. Can (maybe) post the whole catalogue if you want he said that's ok(why wouldn't he,saves him the hassle)
     Cheers fer now duTch
 PS.
when I was about 14, ratted a really old(then) Delco Remy 6v horn from the local tip,think from my mates dads truck- THAT is a HOOTA!! Had on the side of my beeza in the 80's for a bit but too big
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia