Author Topic: Headlight switch confusion  (Read 348 times)

Offline bl**dydrivers

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Headlight switch confusion
« on: 09.12. 2017 01:02 »
I know the switch I need is Lucas 31340, I have an original, but it’s missing parts and the new replica ones have a different layout underneath.

What’s missing?
Can I use parts from a new one?

Want to keep the switch original.

Offline duTch

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Re: Headlight switch confusion
« Reply #1 on: 09.12. 2017 05:18 »

 If you do a search, you should find previous threads about this.....if I can remember I'll do it later too
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

Offline JulianS

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Re: Headlight switch confusion
« Reply #2 on: 09.12. 2017 12:13 »
Probably no parts missing from your original switch.

There are at least 2 versions of the switch.

Terminal 5 - for tail and speedo light needs a fixed contact between the terminal for headlight and the terminal for pilot light.

On your original you will probably find the contact is internal , an internal brass contact in the bakelite between 5 and the brass sleeve in which the rotor moves. Test with a meter and you will probably be able to see the end of the contact if you carefully examine the switch near 5.

First photo is such an original switch.

The pattern switch - ignore the pressed brass bits you dont need them - it has an external contact between 5 and the rotor.

On the original Lucas switch with external contact the stud in terminal 5 was locked with solder.

Second and third photos show an original Lucas switch with external contact.