Unusual BSA frame?

[JulianS]

See this photo from the BSAOC members area. The photo shows the first version of the swinging arm Gold Star frame used only for the 1953 season. The number were prefixed BB32A. They were superseded for the 1954 season by the more familiar CB32 prefix swinging arm frame.

Note the lower frame rails and notice the oil pump kink. The 1953 kink was welded or brazed into the right side tube rather than the tube having a kink pressed in before the frame was welded as on the 1954 on type. Also notice the way the lower tubes run compared to the later version.

I think this may be a repaired/modified BB32A type frame.

[limeyrob]

Well spotted, that could be it.  If so its a rare bike with the correct '53 engine and frame. It certainly looks like its had a hard life.  As other's have said, recent DVLA rule changes have allowed "home" stamping of numbers subject to some conditions but it's certainly a better situation than it was before.
You will need to keep records and especially a purchase receipt to prove you did not steal it.  Having registered a bike recently the DVLA will ask for it to be a complete bike in usable condition so you have quite a bit of work before then!
If the BSAOC dating officer can get a frame number to match that engine (fingers crossed) then things could go smoothly.

[neil1964]

I completely agree, looks like a 53 GS frame.
I had a CB34.xx5 frame that you could not make the numbers out but by polishing where the number was with wet and dry then wd40, more polish the numbers became clearer and legible.

[limeyrob]

Its is possible to use mild acid to show the stamped numbers when they have been sanded off.  They do it for guns and stolen cars, but I've no idea how!
Very interesting bike worth saving.

[JulianS]

The gearbox in the photos is the rigid or plunger frame type. I think it will be very difficult to fit in the swinging arm frame.

[V500]

The engine is from an earlier rigid or plunger bike too, but will fit OK.

[neil1964]

Yep, engine is no problem, just standard s/a engine plates (B31 will do)
Gearbox not as easy, STD s/a boxes are common to A and B models and very easy to source.
(I've got a working spare lying around needing a rebuild).

[JimMc]

Thanks all for the priceless info on this bike, it's a massive help. Got some paint stripper arriving today, I am going to try for a frame number again.

Then the frame will be blasted and any repairs carried out. Thats all over the next 2 months, hopefully!

[JimMc]

Yep, engine is no problem, just standard s/a engine plates (B31 will do)
Gearbox not as easy, STD s/a boxes are common to A and B models and very easy to source.
(I've got a working spare lying around needing a rebuild).

Thanks Neil, if thats an offer to sell the spare gearbox I would be thinking about it. I was going to rebuild the one I have anyway, most likely a post Christmas discussion

[Derek996]

This appears to be a "bitsa"of some sort. The frame could be a heavily modified B31/33 or even from an A7/A10 with that welded kink, although I believe some very early s/a Gold Star frames had a similar kink.
The ZB32GS engine is earlier, originally from a plunger frame although some of the late ZB32GS from engine number 6001 on were fitted to swinging arm frames. There were very few of these.
The gearbox is a 4 speed "Lightweight" box originally fitted to rigid B31/32/33/34 models from 1946 to 1948.

[JimMc]

This appears to be a "bitsa"of some sort. The frame could be a heavily modified B31/33 or even from an A7/A10 with that welded kink, although I believe some very early s/a Gold Star frames had a similar kink.
The ZB32GS engine is earlier, originally from a plunger frame although some of the late ZB32GS from engine number 6001 on were fitted to swinging arm frames. There were very few of these.
The gearbox is a 4 speed "Lightweight" box originally fitted to rigid B31/32/33/34 models from 1946 to 1948.

Thanks Derek, good info on the gearbox, I am planning a rebuild in the new year, I will see if there are any more markings etc.

All - is it prudent/safe to share the engine number?

[V500]

Make the last digit an "X" if you're worried about it.

[TTJOHN]

Jim Mac.
That gear box looks like a standard WM20 one with a broken lug on the top, with a more modern outer box, the broken part is where the cable was secured.

[neil1964]

Yep, engine is no problem, just standard s/a engine plates (B31 will do)
Gearbox not as easy, STD s/a boxes are common to A and B models and very easy to source.
(I've got a working spare lying around needing a rebuild).

Thanks Neil, if thats an offer to sell the spare gearbox I would be thinking about it. I was going to rebuild the one I have anyway, most likely a post Christmas discussion

The offer is there (I've got two but it depends on how much work you want to do!). I am in West Suffolk.  I have a spare exhaust system (B31 '54/55 type with Burgess style silencer) in very good condition that would suit a ZB32 as well as some cams and a special B32GS crank pinion. Also a crinkle rear wheel, couple of oil tanks and some fork legs and brake plates, all of which I've meant to e-bay or list in classifieds but not got round to it yet!

[JimMc]

Jim Mac.
That gear box looks like a standard WM20 one with a broken lug on the top, with a more modern outer box, the broken part is where the cable was secured.

Thanks John