Hi all, apologies for posting the ubiquitous BSA frame type question but I am at a loss with this one. Also, not sure which thread I should post in for this, maybe the "Looking for BSA"?
The previous owner had taken off some of the reinforcement metal at the head trying to find the frame number and it doesnt seem to have one. It looked like someone welded over it, but there isnt a number. I have checked all locations and all over the frame and there isnt a number on it. Also, it's got reinforcement welded in and an unusual metal box section under where the tank sits
It had an oil tank where the battery would go and an airbox where the toolkit would have been. Any ideas at all?
The bike was in bits when we got it, we are trying to identify it so we can rebuild it.
Thanks
https://photobucket.com/share/96d54c61-a3e5-4030-beff-7f50f01d2b10
Sorry, cant seem to insert the URL
It's not an A10.
It looks like a frame for a B31 or B33. No number and a large rap round on headstock usually means that it is a replacement frame from BSA, 1959 on. Dealer would have stamped the old frame number on whilst the old frame was scrapped. My Shooting Star has such a frame.
Hi,
A pre-unit single frame with lots of strengthening. It looks like the front down tubes sustained a fracture just below the head stock and may have suffered similar stress damage to the footrest loops.
Both of these parts of the frame are often used when mounting side cars and then being subjected to a lot of use/stress.
The additional bracing to the head stock would also suggest that stress/load will be part of the life of this frame perhaps in competition. The use a central oil tank and probably a larger air box/filter would suggest the same. It also looks like some of the original fuel tank mounting lugs etc. have been removed and others welded on perhaps for a non-standard tank.
Do you have photos of any other parts such as the fuel tank.
To post images use the box below 'click or drag files here to attach them'. You may need to reduce the size.
Dave.
Thanks all/Dave
I was on the competition side as well, but the lack of frame number meant I was chasing my tail slightly.
The engine we have for it is this - Year 1951, Model B32GS GOLD STAR, Engine prefix ZB32GS, 350cc. The gearbox looks like the same sort of vintage, they dont seem to be orginial to the frame and older. The fuel tank looks standard, I have attached some pics of it and the oil tank. Right now we are doing an inventory, collecting and tagging with the view to reassembly. We had intended in registering it for the road, but right now, it's all a bit of a puzzle. There are a few bits missing, but nothing we couldnt get here etc.
That makes sense. So its competition 350 Gold Star that's been heavily modified, probably for scrambles and perhaps even with a chair. Frame could be a Gold Star frame but later than the engine. What is stamped on top of the gear box?
Hi, just checked the gearbox, and I cant see anything stamped! I have looked all round it, cant see anything. I suppose the millon dollar question is, if the frame has no number, will I ever be able to register it for the road?
I dont mind the work I need to put into the bike, it's as much about sentimentality as anything else.
There is also some small rust holes in the lower frame, where is sat on the ground, but again, I dont mind that sort of thing.
Hi,
A standard road fuel tank but the gear box looks like from an earlier model and not for a swinging arm frame.
As for getting the bike registered for the road, it may be worth asking the BSAOC Machine Dating Officer.
Dave.
Quote from: DAVE BRADY on 16 Nov, 2025, 14:23 Hi,
A standard road fuel tank but the gear box looks like from an earlier model and not for a swinging arm frame.
As for getting the bike registered for the road, it may be worth asking the BSAOC Machine Dating Officer.
Dave.
Thanks Dave
I stand corrected on the gearbox markings. There's not STD or ratio, but there is L C K?
It looks better in real life, the pic makes it look like a cave drawing!
I think the other picture is just damage
Have you checked the steering head for frame number (see atatched of my B33)?
You can still get it road registered - I've had a couple of queries on frames with no / disfigured markings recently, and the info from DVLA is the first thing you need to do is to apply for a new VIN and get that stamped on the frame to identify the machine.
Once that is in place then we can arrange the inspection and vehicle report to support the age related VRN / Reconstructed Classic process.
The contact at DVLA is ....
Kits & Rebuilds
Longview Road
Morriston
Swansea
SA6 7JL
Email: DVLAVIN@dvla.gov.uk
You need to write/email supplying your name, address and reason you require a new VIN.
The club can then help with the Reconstructed Classic application.
Thanks Jabba, very helpful
Also, I have attached some pics, there could be the remnants of a "D" at the bottom, but it looks smaller than the usual stamped characters.
I may try and take the paint off, I though it was surface corrosion, but it may be old primer
Good luck with cleaning up.
One thing - looking at the photo of the frame it does look like the "kink in the lower tube has been brazed / welded in?? Is this the case (difficult to see for sure in the photo) ... if so then probably an A7/A10 frame modified for a single?
Quote from: JABBA99 on 16 Nov, 2025, 15:47 Good luck with cleaning up.
One thing - looking at the photo of the frame it does look like the "kink in the lower tube has been brazed / welded in?? Is this the case (difficult to see for sure in the photo) ... if so then probably an A7/A10 frame modified for a single?
Thats intersting you should say that, I thought there has been some brazing on it, I could maybe take some closer pics and post then for reference. 8)
Thanks again Jabba
Could be brazing?
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.
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.
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.
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.
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.
The engine is from an earlier rigid or plunger bike too, but will fit OK.
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 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!
Quote from: neil1964 on 17 Nov, 2025, 10:58 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
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.
Quote from: Derek996 on 18 Nov, 2025, 09:46 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?
Make the last digit an "X" if you're worried about it.
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.
Quote from: JimMc on 17 Nov, 2025, 11:16 Quote from: neil1964 on 17 Nov, 2025, 10:58 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!
Quote from: TTJOHN on 18 Nov, 2025, 18:31 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
I could be interested in the exhaust system. Is it low level, standard or upswept? It's for a 1951 ZB32.
Quote from: neil1964 on 18 Nov, 2025, 21:00 Quote from: JimMc on 17 Nov, 2025, 11:16 Quote from: neil1964 on 17 Nov, 2025, 10:58 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!
Thanks Neil, if it's not too urgent, then I would have a look at this in Jan/Feb, but it's exaclty the sort of thing I am looking for, I just need to complete the inventory. I know most of the wheel assemblies are gone, and the forks look a bit ropey, and other bits and peices that would get lost over time once a bike is disassembled. I should know in the next few weeks what we have, bit if you need to move them on before then, thats all good too. Happy to discuss
Quote from: V500 on 18 Nov, 2025, 18:02 Make the last digit an "X" if you're worried about it.
;D sometimes the simplest solutions are thge best! thanks
ZB.32.GS.30xx
Quote from: JimMc on 18 Nov, 2025, 21:20 Quote from: V500 on 18 Nov, 2025, 18:02 Make the last digit an "X" if you're worried about it.
;D sometimes the simplest solutions are thge best! thanks
ZB.32.GS.30xx
1951, with cast in rocker box.
Quote from: TTJOHN on 18 Nov, 2025, 18:31 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.
I had a close look and you are correct. The broken off speedo drive is the give away. Here are pictures of both boxes. You'll see the apart from the speed drive the casting below the clutch lever is different with a more prominent bulge.
Quote from: Derek996 on 19 Nov, 2025, 10:40 Quote from: TTJOHN on 18 Nov, 2025, 18:31 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.
I had a close look and you are correct. The broken off speedo drive is the give away. Here are pictures of both boxes. You'll see the apart from the speed drive the casting below the clutch lever is different with a more prominent bulge.
Thanks both, invaluable info
Quote from: JimMc on 18 Nov, 2025, 21:19 Quote from: neil1964 on 18 Nov, 2025, 21:00 Quote from: JimMc on 17 Nov, 2025, 11:16 Quote from: neil1964 on 17 Nov, 2025, 10:58 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!
Thanks Neil, if it's not too urgent, then I would have a look at this in Jan/Feb, but it's exaclty the sort of thing I am looking for, I just need to complete the inventory. I know most of the wheel assemblies are gone, and the forks look a bit ropey, and other bits and peices that would get lost over time once a bike is disassembled. I should know in the next few weeks what we have, bit if you need to move them on before then, thats all good too. Happy to discuss
No rush. The pipe is low level and would be suitable for B31 or ZB32 (early long rod) and s/a frame, c/w clips and finned top clamp