GB44 Mainshaft

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Mick D
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GB44 Mainshaft

Postby Mick D » Sun Dec 16, 2018 5:31 pm

Hi
I'm in the process of checking / overhauling a spare gearbox which came with my 58 FH - I hope it's the original as the bike currently has a GB6 fitted.
I understand the differing lengths of main shaft but cannot find a definitive of where the plain shaft dimension is taken. Could anyone advise please or identify which shaft I have from the attached image?
GB44 Mainshaft.png
GB44 Mainshaft.png (164.55 KiB) Viewed 570 times

Regards Mick

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marcus whatling
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Re: GB44 Mainshaft

Postby marcus whatling » Sun Dec 16, 2018 6:56 pm

Hi Mick
Have you see the details on Draganfly,.s site https://www.draganfly.co.uk/data/pdf/gblengths.pdf

Mick D
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Re: GB44 Mainshaft

Postby Mick D » Sun Dec 16, 2018 7:37 pm

Hi Marcus
Yes, I've read that but as the gearbox is in bits I'm struggling to work out what I have. It would be great if someone could indicate how the plain shaft dimension is determined.
Regards Mick

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paul.jameson
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Re: GB44 Mainshaft

Postby paul.jameson » Sun Dec 16, 2018 8:30 pm

The mainshaft in the photo is correct for a GB44 gearbox. If you had the shorter one from a GB6 gearbox to hand, the difference would be more obvious. Don't overlook the possibility that someone has replaced the original shaft in your GB6 box with a longer one. It doesn't take long to do the swap and is guaranteed to confuse subsequent owners of the bike.
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.

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keith.mettam
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Re: GB44 Mainshaft

Postby keith.mettam » Sun Dec 16, 2018 8:32 pm

Hi Mick, from what I can see of your image you almost certainly have the correct full width hub mainshaft which caters for the extra width needed for Ariel's fully enclosed rear chaincase or FERC as it is known. Here is a document I have that shows the different GB gearbox mainshaft dimensions :-
GB Mainshaft dimensions.jpg

All the best with it and season's greetings, Keith.

Mick D
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Re: GB44 Mainshaft

Postby Mick D » Mon Dec 17, 2018 8:48 am

Thank You Gents
You have confirmed my hope and that drawing illustrates where the dimension is measured.
When I get around to removing the currently installed GB6 gearbox I'll use the drawing linked above to ascertain what shaft is fitted.
This is my first excursion into Ariel restoration - I must say I'm really enjoying it so far.
Regards Mick

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Re: GB44 Mainshaft

Postby Mick D » Sat Jan 19, 2019 1:14 pm

Hi
Just to bottom this one out, I've now stripped the bike far enough to be able to measure the main shaft on the installed, (GB6), gearbox in accordance with the link provided by Marcus - it's a 3630-52, (correct for a GB6 but not for the FH), so the spare GB44 box will get re-furbished and fitted.
I had to source a 1" Whitworth spanner to remove the gearbox sprocket nut as I didn't have one and the forward section of the FERC didn't allow access with my large adjustable - got one from here:
https://www.ffx.co.uk/tools/product/Mel ... -X-1-X-7In
Very happy with the price, product and 3 day delivery.
The plan is coming together :D
Regards Mick


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