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Speedo gearbox question

Posted: Fri Dec 15, 2017 8:02 pm
by OlofMelander
New to the forum, I have a question regarding the W/NG speedo gearbox.
My bike did not have the gearbox, I have just purchased one that according to the seller is for W/NG and now I am having a discussion with them if it is the correct type.
Looking from above at the output / cable connection point, should this rotate clockwise or anti clockwise? The one I got is anti clockwise.

I hope that the collective wisdom of the forum can help me out here.

Re: Speedo gearbox question

Posted: Sat Dec 16, 2017 7:40 am
by adrie.degraaff
WNG speedo is driven from the frontwheel, the box is blocket or has a solid casting there.

Re: Speedo gearbox question

Posted: Sat Dec 16, 2017 8:21 am
by RTichard Woolnough
If you go to my old posting of 'W/ng' purchase you will see a picture of the front of a W/ng on page four there is one showing the arrangement of the speedo drive location, kind regards

Re: Speedo gearbox question

Posted: Sat Dec 16, 2017 10:07 am
by OlofMelander
Thanks for answers but my question was probably a bit unclear so let me rephrase it.
I know that the gearbox shall be fitted to the front wheel hub, and in case of the W/NG on the right hand side so that is not a problem, what I need to know is if I have got the correct type as they, as far as I know, were made in different variants to fit left side or right side. I have found some documentation that claims the output should always be clockwise rotation regardless of which side of the wheel it is attached to.
The gearbox I have got now will give anti clockwise rotation output if used on the right side but clockwise rotation if attached to left hand side (suggesting it might not be suitable for the W/NG)

The question boils down to if the Smiths chronometric speedometers require a specific rotation direction of the incoming drive wire or if they work regardless of clockwise or anti clockwise rotation.

Re: Speedo gearbox question

Posted: Sat Dec 16, 2017 10:43 am
by nevhunter
The speedo has to turn the right way. While the bobweights in some speedo's might work in both directions the mileage counter won't. The chronometric is It's own magic that I know nothing about. Nev

Re: Speedo gearbox question

Posted: Sat Dec 16, 2017 11:05 am
by simon.holyfield
Sorry for this news...

Viewed from above, the cable connection to my RHS mounted speedo gearbox turns clockwise.

Re: Speedo gearbox question

Posted: Sat Dec 16, 2017 4:16 pm
by RTichard Woolnough
have a word with those on the BSA WD M20 forum they maybe able to I/D your drive box, there are lots of postings re these items which I'm afraid are very difficult to source. kind regards

Re: Speedo gearbox question

Posted: Sat Dec 16, 2017 11:28 pm
by Vincent.vanGinneke
I have the same anti clockwise gearbox fitted and figured out that my gearbox is for a Norton 16H.
It is now not connected to the speedo as I took out the cable.
So now there are two who are looking for the correct gearbox..... :D

Re: Speedo gearbox question

Posted: Sun Dec 17, 2017 12:08 am
by nevhunter
Make that 3 . I need one too.. It's different to the Norton. You need the steel drive gear and pin as well that goes on after you have screwed it in. Nev

Re: Speedo gearbox question

Posted: Sun Dec 17, 2017 1:45 am
by simon.holyfield
Drags have the gears folks.