Author Topic: headlamp bulb  (Read 202 times)

Offline jonny web

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headlamp bulb
« on: 25.09. 2019 22:41 »
Im fitting an old lucas catseye headlamp lens into a fairly modern reflector which takes the standard headlamp bulb with a flat flange and a notch which locates on a groove in the back of the reflector, I m not sure if the groove in the reflector should be at 12 o clock or at 6 o clock ?
cheers
JW

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Re: headlamp bulb
« Reply #1 on: 25.09. 2019 23:10 »

 
Quote
.................which takes the standard headlamp bulb with a flat flange and a notch which locates on a groove in the back of the reflector, .............

 Sounds like the ones with a base known as 'BPF' (British Pre Focus) but can't help other than suggesting if there's numbers or letters on the glass that may indicate 'Top' .......other than that, any 'throw' pattern on the glass probably should give an indication  *dunno*
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Offline jonny web

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Re: headlamp bulb
« Reply #2 on: 26.09. 2019 07:10 »
yes the glass has top on it but the glass is not attached to the reflector yet and i need to know which way up the reflector goes so that the dip beam filament is in the right place
hence does the slot go underneath or on top

Offline Swarfcut

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Re: headlamp bulb
« Reply #3 on: 26.09. 2019 09:39 »
To add to the confusion, a quick Google search of Lucas Prefocus Reflectors brings several images with a rear view of the bulb housing.

Swarfy.

Online JulianS

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Re: headlamp bulb
« Reply #4 on: 26.09. 2019 10:34 »
Photo is an old Lucas "Motor Cycle" verticle dip pre focus unit.

The pen tip shows the top.

Hope this clarifies.

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Re: headlamp bulb
« Reply #5 on: 26.09. 2019 12:59 »
Not sure if I am missing something here but is it not just a case of keeping the hole for the pilot lamp at the bottom below the main bulb?
You may need to file a new groove to locate the glass up the right way.
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Re: headlamp bulb
« Reply #6 on: 26.09. 2019 16:26 »

 
Quote
Not sure if I am missing something here but is it not just a case of keeping the hole for the pilot lamp at the bottom below the main bulb?
You may need to file a new groove to locate the glass up the right way....

 I thought same, but think you missed that it's upside down ( "The pen tip shows the top ")
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

Offline jonny web

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Re: headlamp bulb
« Reply #7 on: 26.09. 2019 19:17 »
thanks everyone for the excellent feedback, I did seem to remember deep in the past that the slot was in the bottom, and this would seem to be correct. My reflector has no pilot light. so i can put the catseye into it now the right way up ! a bit of silicone on the rather old rubber sealing ring and then gently crimp the reflector bezel over the glass.
cheers JW