Thread Size Headlight Bolts

[Carts]

Hi all

Can somebody confirm the thread size for the nut inside the headlight, this is the 2 that attaché to the bracket on the forks. measures 10.5 mm so not a metric size

Just after this as after having a different indicator stem made, and I don’t have any thread gauge to check TPI

[3potjohn]

Not the answer I am afraid, as what I did was to drill through then retap to suit my replacement indicators from Vehicle Wiring Products. I used these as my Sport had originally a rectangular headlamp and nose fairing.It had been replaced with a Cibie unit. The indicators are cheap, easy to obtain, somewhat flexible and visible in bright sunlight.
Someone should be along with the correct info soon.
John

[George 350]

For bikes up to 1978 at least, the CEV round headlamp shell captive 'nuts' are/were M8x1.25.
The CEV 18343 indicators are/were fitted with an M10x1.5mm nut inside (standard ISO M10, Not the Japanese 1.25 pitch).
Hope this helps.
George

[Carts]

Thanks all, looking at the thread I don’t think it’s a M10. I’ll go and check tomorrow

[George 350]

Back to your original post, 10.5mm is very close to 7/16". The 'Lucas' indicators as fitted to Bonnies, Commando's etc had a 7/16" UNF thread. Wonder if a previous owner modified your bike to take these?
Just a thought....
George.

[Carts]

Hi I’ve tried to add a pic, but file size to big.

I think the indicator stems are standard units NLM put on 350.

[Steve Brown]

Carts, that sounds like what George is suggesting. A lot of people used Lucas pattern indicators as they look fairly similar to the original CEV lamps. NLM did it too and those Lucas lamps have the right thread to fit a Lucas style headlamp. Lots of folk did that including me, to get a better headlamp or replace a broken original.
So if your lamps do have a 7/16" UNF thread....

[Carts]

Thanks all

[George 350]

Correction: Checked the Lucas indicators on my Norton and stems have a 7/16" UNC, not UNF thread. 14tpi not 20tpi.
sorry.