Can you identify this motorcycle?

[Michael GilliganParticipant @michaelgilligan61133]

Yes, I know, Robert

… I was simply picking-up on what I quoted from your previous post.

MichaelG.

[Robert ButlerParticipant @robertbutler92161]

MichaelG the images in your latest post show an oil tank missing from the OP image.

Robert Butler

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robert Butler on 23/01/2022 23:08:22:

MichaelG the images in your latest post show an oil tank missing from the OP image.

Robert Butler.

.

… and the relevance of that fact is ??

I simply posted a side-by-side pair of images for comparison and consideration.

We have already established that the C10 came in many flavours … and for all I know, the one in the opening post may be a bitza [or even something entirely different].

Off to bed now.

MichaelG.

[Robert ButlerParticipant @robertbutler92161]

MichaelG I agree but they are dry sump and need a separate oil tank and the tank either mirrors the expected design or sort of rectangular. Also missing in the OP image is the alloy valve chest cover present on all other images.

Regards

Robert Butler

[duncan webster 1Participant @duncanwebster1]

Most small 2 strokes would have flywheel magneto, not a drive up to a dynamo. C10 had battery and coil ignition, you can just make out the distributor. As to the lack of an oil tank, we'll you can't see the gearbox either, but I'll bet it's got one. Exhaust would be lower down on 2 stroke as well

[David Davies 8Participant @daviddavies8]

As Duncan says it is a BSA C10. The oil tank would be behind the girl's calf and the gearbox would be behind her heel. The carb connects to the barrel not the crankcase so clearly a SV 4 stroke. Fortunately the C10 and the C11 were replaced by the C15, a much better bike IMHO and on one I passed my test in '76.

Cheers

Dave

[SamsarandaParticipant @samsaranda]

Pre war two stroke Triumph. Dave W

[Fowlers FuryParticipant @fowlersfury]

Interesting change from model eng !
Seems 2 serious contenders for consideration. I had some vague thought (as usual) that Triumph made many similar-looking bikes for the War Office in WWII and found the pic of the 3TW 350 sv complete with female riders.
Yet there was quite some support for the Beezer M20. Taking the op's original image, there wasn't much that even Photoshop could do with it. However, it would seem that the M20 and 3TW might have had the same basic engine in wartime and shortly thereafter. The alloy covers for the dynamo drive look virtually identical. The tappet adjustment covers are only slightly different. The BSA shows a vertical indentation in the cylinder fins not apparent on the Triumph.
I doubt we'll get nearer to a definitive identification given the poor quality of the original image.
The bike was probably a "bitsa" anyhow.

I have an original copy of Motor Cycling dated July 30th 1942 which has an illustrated article about army maintenance of m/cycles but doesn't contribute to the op's question. However there are within, fascinating bits about the compulsory purchase of m/cycles for military use as well as a form to complete so you could volunteer as a local dispatch rider !

[JohnFParticipant @johnf59703]

Posted by duncan webster on 24/01/2022 00:21:29:

Most small 2 strokes would have flywheel magneto, not a drive up to a dynamo. C10 had battery and coil ignition, you can just make out the distributor. As to the lack of an oil tank, we'll you can't see the gearbox either, but I'll bet it's got one. Exhaust would be lower down on 2 stroke as well

I agree with Duncan, look at these photo's you can see there are two filler caps on the tank and its not unknown for the oil tank to be part of the fuel tank, this clearly has a dynamo & there is also a distributor at the front of the engine indicating a 4-stroke — same as on the C11, C11G & C12 — C11 was my first bike. Timing chain/dynamo drive cover is the right shape plus as Duncan rightly says I cannot recall ever seeing a 2 -stroke with a dynamo, they had a magneto & points mainly on the LHS of the engine.

John

[Clive FarrarParticipant @clivefarrar90441]

don't know about the frame but the engine looks like a Villiers 197 to me.

Worked on one many moons ago. Which coincidentally went into a James trials frame with telescopic forks.

Although having quickly checked some on line images that engine doe's not have an eliptical side case like the OP picture So I am wrong.

Regards Clive

[SamsarandaParticipant @samsaranda]

Duncan some pre war two strokes had a magneto in the same position as in the photo. Dave W

[SamsarandaParticipant @samsaranda]

I would suggest that the specimen is definitely two stroke with the flat cylinder heads with no valve gear and unlikely to be side valve because although the picture is poor there doesn’t appear to anywhere for side mounted valves. Dave W

[ChrisLHParticipant @chrislh]

In favour of the Triumph, the front fork damper adjustment appears to be in the forwrd position as in the OP whereas the BSA is rearward ?

[mgnbukParticipant @mgnbuk]

I would suggest that the specimen is definitely two stroke

I would equally suggest that it isn't – the position of the carb & exhaust outlet are just too far up the barrel to be a two stroke, but just right for a side valve.

Nigel B.

[Tim HammondParticipant @timhammond72264]

It's a real puzzler this one – I agree with Nigel B that the position of the carb. and the exhaust pipe seem too high for the engine to be a 2-stroke.On the other hand, on the photos of the various makes of SV motorcycles, the tappet chest covers are quite prominent, whereas there doesn't seem to be one on the original photo. Perhaps after all it is a Bitza – a B.S.A. – Bits Stuck Anywhere !

[Michael GilliganParticipant @michaelgilligan61133]

This discussion is reminding me of Antonioni’s Blow Up of 1966

**LINK**

https://artblart.files.wordpress.com/2014/07/david-hemmings-in-blow-up3-web.jpg

MichaelG.

[noel shelleyParticipant @noelshelley55608]

I don't know what year or make but the position of the carb and exhaust mean it is in my opinion a 4 stroke side valve. Noel

[ChrisLHParticipant @chrislh]

Regarding Tim Hammond's observation re. tappet chest covers, could it be that the OP's engine was an economy version where black painted pressed tin had been substituted for polished cast ali. ?

[norm nortonParticipant @normnorton75434]

Well this thread has caused fun!

Just as Noel says, and Duncan, the position of the exhaust and carb makes it a four stroke and the shallow head says side valve. The poor image makes it impossible to see the side valve chest cover that should sit just below the barrel, presumably it has been painted black.

This first image is of a 1940 BSA M20, side vale single, but the cover for the magneto chain is not quite the right shape.

 

This second image is of a 1951 BSA C10, side valve single, and the chain cover is the right shape. Obviously this 1951 model has telescopic forks but a BSA marque expert would have to say whether this engine first came out in a rigid frame with girder forks a few years earlier.

Edit: yes, found C10s going back to 1939 link

Previous identification by Micheal and JohnF acknowledged.

 

Edited By norm norton on 25/01/2022 10:34:10

[HopperParticipant @hopper]

For my money also it's an early BSA C10. 1939ish or very immediate post war perhaps You can't see the oil tank or the tappet cover because the photo is horribly underexposed (as well as out of focus) so those areas are just black blobs. But you can see a very blurry image/blob of the points "distributor" housing sticking out of the cam timing chest at the 2 o'clock position, which is uniquely C10 AFAIK.

The big 'uns had magnetos up behind the cylinder and the two strokes had flywheel magnetos. The C10 had that unusual points housing.

I believe you can see the blur of the ignition coil above the cylinder head, under the petrol tank, in the OP picture, which matches the photo of the later model ignition coil Norm Norton posted above. Coil ignition was pretty unusual on Brit bikes in 1939, with most using magnetos, so the humble C10 was ahead of its time in one way at least. That's why the other bikes of the day did not have that points housing sticking out like that.

Edited By Hopper on 25/01/2022 11:07:50

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