BSA Quiz

[Tomcat]

Could one of the learned BSA folk please identify this gearbox for me?

[Tomcat]

smore

[Tomcat]

Last pic

[muskrat]

Maybe a 3 speed from the 20's.
Cheers

[RichardL]

I have an unhealthy desire to win this quiz.

By pure research (that is, no first-hand knowledge), I believe at least one of the models using this gearbox was the 1931, L31-6. Scroll down to rebuild pictures in this link: http://www.nsmb-restorations.co.uk/gallery.php?pageNum_gallery=3&totalRows_gallery=55 . Looking closely, you can see the patent numbers match.

Then, you can Google L31-6 and see many confirming images.

Richard L.

[JulianS]

I think it looks like the parts indicated with arrow from the 1926 parts book.

The key in second photo shows parts fitted to the 3.49 HP side valve and overhead and the 4.93 HP model.

I dont know what the 2 sprockets are for.

There are similar illustrations in parts books up to 1932.

[Greybeard]

I dont know what the 2 sprockets are for.

I've been pondering that. Maybe the box has been adapted for use in something else; a saw bench or a lathe for example and the input gearing has been changed to give faster output revs. I see the kick-start has been hacked off. The hole drilled in the nameplate might indicate an easy lubrication point for such a machine. May have had a cork in it once.

Found this: https://youtu.be/n5YtMRlMzQE

[chaterlea25]

Hi Tomcat,
Indeed a 20's 3 speed box, These came in a couple of sizes though to the best of my knowledge
Could you give some measurements say of the distance between the mounting bolts? and the front to back and height of the cover
I can compare these against the box in my 350 L25
I agree that it has been used for some other purpose ? original oil level and filler plug are at the back of the main case

John

[RichardL]

As John and Julian note,  originally deployed in the 20s and used through 31. I think they changed for 32. I'm going to edit this post to add a brochure from 1930 showing some other usage.

Frustrating when you can't re-find something on the web. Here are the 1931 models. Seems to me that they rotated the gearbox when used with the sloper.

http://www.bsa1930s.nl/1931.htm

Ah! Here are the 30's models: http://www.bsa1930s.nl/1930.htm

Richard L.

[Tomcat]

Thank you all for the research and replies gents, it looks like 1926 to 1931 from the above information.
 The measurement between the mounting bolts is 120mm John. The gearbox was used in a Bag Loader and that's why the odd sprockets were fitted. 
Cheers Peter

[RichardL]

Well, maybe this should be over, but it seems to be the quiz that keeps on giving. It looks like that gearbox goes even further back. Check out the pictures of this 1923 flat-tanker. I came on this because I was wondering if bikes from the era were up for offer (but with no intent of buying).

http://www.ebay.co.uk/itm/1923-BSA-L23-350cc-VINTAGE-BRITISH-CLASSIC-FLAT-TANKER-TAX-MOT-EXEMPT-/162521237371?hash=item25d705477b:g:Yu4AAOSw~CFY8HsQ

Richard L.

[chaterlea25]

Hi Peter,
The 120mm matches up with the mounting centres on my L25
Richard,
Yes the L series started for the 23 season, the OHV engine changed in internal design a couple of times after the initial version
different main bush/ bearings and different conrod and big ends,
The oil pump /feeds changed for 1927 season
My "L" is a work in progress, I got a very good set of front forks for it recently saves me having to rebush and make new links and so on for the ones that came with it
I now have all the bits to rebuild the engine top end too

John

[RichardL]

...and, apparently, a (spare?) gearbox from Tomcat if you need it.

Richard L.

[chaterlea25]

Hi Richard,
After I bought the L25 I took it for a short ride,
My conclusion that the only aspect that did not need major attention was the clutch and gearbox 
Don't put a "hex" on me so that I will have to rebuild those too
The gearbox and bottom end have to come out anyway to repair the footrest mounting that consists of a hexagon bar through the gearbox plates, the hexagon holes are worn to death, I am going to weld in sections of a single hexagon socket to restore the fit

John

[RichardL]

Very clever, but expect no less from you.

Richard L.