Is this Gearbox correct for a '56 NH

[dennis.t]

I have a gearbox with the following codes on it. On the top it shows BSK 54 -940 and GB 45. On the side it shows VAF and G-1-5.
Is that correct for a'56 NH, or at least workable? The gearbox sprocket has 19 teeth. The engine and gearbox may have been used for racing.
The Drags list shows, I think, GB 39 for the model and year. I have no idea what the difference is between the GB 39 and GB 45 gearboxes.
Many thanks,
Dennis

[will_curry]

Interesting set of numbers. There is usually a date code of one letter A to L and 2 numbers
where the letter represents the month and the numbers the year. This might just be the
K54 on your 'box which would equate to November 1954. This is unlikely as G45 gearboxes
didn't appear until 1956 and then only on the HS scrambler. As far as I know, the only difference
between G45 and the road boxes was that G45 had a folding kickstart and a competitions clutch.

The 'gotcha' with Ariel Burman GB boxes is the length of the mainshaft which changed from 1955
to 1956 with the latter being slightly longer and making the gearboxes not interchangeable although
very, very similar.

There is a very useful article on Draganfly's website at:

https://draganfly.co.uk/wp-content/uplo ... engths.jpg

[JohnnyBeckett]

hi i have GB 54 on my 1953/54 nh and 55 on my 56 nh i know the gearbox main shaft is longer on the 56 because the 56 has got wider hubs with bigger brakes , and i think most parts in the GB boxes can be interchanged

[will_curry]

My understanding is that both the gearbox mainshaft and the in the case of the singles
the driveside mainshaft in the crank were extended to move the primary drive outboard
to make room for the fully enclosed rear chainguard option.

[dennis.t]

Will,
Many thanks i will check the length of the main shaft.
Dennis

[paul.jameson]

The detail on how to identify the mainshaft is in the Draganfly catalogue. One point worth remembering is that Burman supplied Ariel with gearboxes which came complete with clutch. Thus a GB5 gearbox is identical to a GB6 gearbox but the GB5 has a 2 plate clutch whilst the GB6 has a 3 plate clutch.

[Mick D]

Hi

I found the information in the Draganfly catalogue lacking in where exactly to take the measurement, the diagram kindly supplied in this thread clarified it:

viewtopic.php?t=8843

Regards Mick

[dennis.t]

Mick,
Very useful thank you.
Dennis