Author Topic: new member first question  (Read 589 times)

Offline cznorbert

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new member first question
« on: 14.04. 2021 14:38 »
Hello, I am Norbert from Hungary. I bought my new bike these days.
Could you help me the identify the exact type?

According to the seller, this is a BSA A7S from 1950.

I don't know, what does "S" mean in the end.

Maybe a Star Twin?

Thank you

Offline Topdad

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Re: new member first question
« Reply #1 on: 14.04. 2021 15:09 »
Hi from sunny Liverpool, I beleive it denotes a spring ( plunger )  frame rather than ridgid , someone will be along to make sure that is correct, hope you enjoy the bike , Bob
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Offline a10gf

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Re: new member first question
« Reply #2 on: 14.04. 2021 16:44 »
Fantastic looking bike, congrats. A member from Hungary, nice. Welcome!

A10 GF '53 My A10 website
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Offline Simon59

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Re: new member first question
« Reply #3 on: 14.04. 2021 17:25 »
I think the A7S was known as the Star Twin, and had a plunger or rigid frame.

Do you have any historical documents that came with the bike? That might confirm the model that you have.

A very nice bike looking Norbert, you must be very pleased with your purchase.
Restored a 1954 plunger framed A10 Golden Flash - now finished!

Online scotty

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Re: new member first question
« Reply #4 on: 14.04. 2021 17:42 »
Welcome Norbert

Great looking bike !

S

Scotty

Current liabilities:
'56 A10 Red Flash
'54 B33
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Online Greybeard

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Re: new member first question
« Reply #5 on: 14.04. 2021 20:31 »
Beautiful motorbike! 😍

 *welcome*

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Re: new member first question
« Reply #6 on: 14.04. 2021 20:51 »
It's a long stroke plunger A7 but not the twin carb Star Twin variant. A very nice example.
2 twins, 2 singles, lots of sheep

Offline muskrat

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Re: new member first question
« Reply #7 on: 14.04. 2021 21:00 »
G'day Norbert  *welcome*
Very nice looking bike mate.
Yes as others have said "S" means sprung frame (plunger rear suspension).
Your 1950 model would be one of the last long strokes. Mine being a 1951 is the first of the short strokes.
1950 numbers, Engine ZA7-7001 and upwards for the standard A7, ZA7S-4001 and upwards for the Star Twin. Frame ZA7S-6001 and upwards. The "S" frame started in 1949 year models.
You would have found we have a Long Stroke section in the forum https://www.a7a10.net/forum/index.php?board=38.0
Cheers
Black Sheep got in first.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline cznorbert

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Re: new member first question
« Reply #8 on: 15.04. 2021 07:43 »
Thank you for the greeting, and information about "S", type is clear.

unfortunately I have not any historical documents

frame number is ZA7S 3709, motor nr. ZA7S 1489

but I found further number, on the frame: YA7 2324, and motor:YA7 2313, what these are mean?

It's great looking bike, and very rare and amazing bike in Hungary, and good to drive, great sound, as you know, I love it

but painfully, same chrome parts (mainly petrol tanks and wheel rims) have defects, rust




Offline Swarfcut

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Re: new member first question
« Reply #9 on: 15.04. 2021 09:10 »
Hi Norbert, Welcome to the Forum.

  The bike frame ZA7S series is a sprung type frame, that is what the S means. In this case spring plungers instead of a rigid frame.  The Z and the number tells you the year. All frames of this design are marked A7. The YA7 number would be from an earlier rigid frame.

 The engine number is a similar system , an S means Star Twin, the more sporty and upmarket model.

 Your frame numbers   ZA7S 3709 put it at around 1950, but earlier than the 1950 model year  where numbers start at ZA7S 6001

Engine number ZA7S 1489 is contemporary with the frame, 1950 model year starts at ZA7S 4001. So actual year of manufacture likely to be 1949 for both.  YA7 2313 is a standard A7 engine number, again from an earlier date.

 The Y numbers seem out of place.  Original frame number is stamped on the left hand side of the steering head frame lug, engine number on left side of crankcase, at the front side just under the cylinder barrel. Y numbers are before 1949. The engine is a late  Longstroke type, with the extra  lower centre bottom bolt on the timing cover. Earlier engines have just two, and the timing cover has a flat bottom. Plenty of scope here for mis representation, so be cautious and check everything.

 The bike has been rebuilt to a high cosmetic standard, retains the  correct earlier smaller front brake and is fitted with a later type front mudguard. All in all it looks a good example.

 Check the number of teeth on the rear sprocket. 49 teeth mean the sprocket is from a low geared sidecar bike. 46 teeth was standard, 42 teeth can be fitted for more speed or higher geared cruising.

 All frame parts interchange with later models, but the engine shares few parts with the later designs. The magneto is marked with the month and year of manufacture. The carburetter  fitted is a modern type, not the original remote float bowl type. These Longstroke  type  engines are prone to camshaft wear, regular oil changes are essential.

 Gearbox looks to be the correct early type, with no grease nipple for the clutch lever pivot. Here again, most parts interchange with later variants, but the gears and layshaft have detail differences if replacements are ever required.

 Swarfy.


Offline trevinoz

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Re: new member first question
« Reply #10 on: 15.04. 2021 22:25 »
The front mudguard is correct for a long stroke Star Twin.

Offline cznorbert

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Re: new member first question
« Reply #11 on: 16.04. 2021 06:44 »
I send pictures of the numbers, both are included
Strange, isn't it?

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Re: new member first question
« Reply #12 on: 16.04. 2021 06:58 »
I would not trust either of these numbers. Someone has stamped these ones - you do wonder just what has been going on. Has it been stolen at some point?
2 twins, 2 singles, lots of sheep

Offline Swarfcut

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Re: new member first question
« Reply #13 on: 16.04. 2021 09:14 »
 Norbert. Trev's right, the valanced front guard is from 1949, earlier models don't have the deep sides.  Musky's A7 has the shallower front mudguard for comparison.
  The  crankcase numbers certainly look suspect, but stamped with the same larger 7 (maybe) and all from the same set of stamps?

 Crankcases are sometimes stamped with a date. Right side, near the oil pressure relief valve, under the dynamo position. Primary side, crankcase stamped next to the tensioner, or in some cases on the flat area where the tensioner blade fits. Worth a look if and when, however not all  are stamped.

 As long as you have title and can use it on public roads that is what counts.  It is certainly a bike with an interesting history. Factory records may show where those numbers started out or indeed if any are genuine.

 Swarfy.

Online bsa-bill

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Re: new member first question
« Reply #14 on: 16.04. 2021 10:13 »
Welcome Norbert
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco