Vintage Workshop
Services for Brough Superior motorcycles and their contemporaries

Sturmey Archer gearbox page last update: 7/2003


OK, it is about time that something happens in this department.

I have, over the last years, tried to get hold of a 4-bolt, HW 3-speed gearbox and a suitable clutch. Now I have got one HW box with standard ratios (1.0 - 1.66 - 2.94) and a LW one with close ratio gears (1.0 - 1.47 - 2.64).

And I have got a nice hit'n miss lever. Ok, the lever itself is a bent, rusty bit of scrap, but the bottom part has a stamping "SB1" on it, which might mean it came off a Special Brough gearbox!
Unfortunately both 'boxes have taper clutch fit main shafts.
And the good 6-spring clutches have a 6-spline fit.

(well you cannot see this on this picture)

So I had to buy still another box with the right main shaft.

The shell of this gearbox seemed quite unusual to me, but now I learnt it is a LS250 type which was used on the Ariel sloper models. It is for sale or swap if you are interested.

Dare I say it is better made than the ones used on Broughs? With internal indexing? Hmm...

Incidentally, I have now made my own castings for the HW gearbox cover with the long stud that was used on the later Broughs having twin silencers on the right hand side.

The problem is that you need a quite long kickstart shaft here, and if you do not have the cover with the large Kickstart boss, cracks are very likely to come up...

This is just the base plate of the casting pattern. Again the rotary table on my FP1 proved very useful.

Now, the said boss is already on the pattern.

Now, this is the finished pattern.

And this is the casting.

I have now started machining them, if you are interested, please have a look here.

These are the finished covers.
If you need one, please have a try and ask me. Maybe there is still one left...


Any kind of feedback to is appreciated
(sorry, this is not a clickable 'mailto:' hyperlink. If you want to write me, please type my address in your mailer. )

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