Author Topic: what did i buy? a 500 or 650?  (Read 2501 times)

Offline mario medeiros

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what did i buy? a 500 or 650?
« on: 15.10. 2013 00:24 »
Can't seem to get pics???how do i tell the differance between a a7 and a10 motor? it is a swingarm frame and the top of the tranny say std and the motor has a alloy head?is there a give away between the 2 motors?Thanks

Online Brian

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Re: what did i buy? a 500 or 650?
« Reply #1 on: 15.10. 2013 01:39 »
Mario the engine number will tell you.

The number is stamped at the top of the crankcases on the left side, just under where the barrels bolt on. It will either have A10 or A7 stamped in along with some other numbers and letters. If you post the full engine and frame numbers we will be able to tell you what year your bike is.

The frame number is located on the left side frame rail just in front of the fuel tank.

Offline mario medeiros

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Re: what did i buy? a 500 or 650?
« Reply #2 on: 15.10. 2013 01:53 »
Problem is I can not read either number as someone at one time stamped over them? I was told to count the number of fins on the barrels to tell is a a7 7 fins and a a10 being 8 fins?

Offline a10gf

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Re: what did i buy? a 500 or 650?
« Reply #3 on: 15.10. 2013 02:27 »
Welcome to the forum, am hoping you will find all the help you may need.

Info about posting pictures: http://www.a7a10.net/forum/index.php?topic=427.0

An introduction post in 'Bikes, Pictures & Members' is always appreciated by all.

A10 GF '53 My A10 website
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Offline Beezageezauk

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Re: what did i buy? a 500 or 650?
« Reply #4 on: 15.10. 2013 09:01 »
Hi Mario,

I also offer you a warm welcome to the forum.

You are correct.  The number of fins on the barrel will tell you if it is from a 500 or 650cc engine.  7 fins on an A7 and 8 on an A10.

Beezageezauk.

Online bsa-bill

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Re: what did i buy? a 500 or 650?
« Reply #5 on: 15.10. 2013 09:20 »
And another welcome to the gang from NE England Mario
Does it run?
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

Offline muskrat

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Re: what did i buy? a 500 or 650?
« Reply #6 on: 15.10. 2013 12:44 »
G'day Mario,  *welcome*.
With the numbers obliterated it will be very hard to tell how she left the factory (not many are that way now anyway).
Give us an intro in Bikes, Pictures & Members section and tell us about yourself and the bike. A few pictures (a10gf's link will tell you how) will enable us to have a guess at what she is, or pretending to be. The A7's go quite well for a 500 and rev hard, the A10's have a bit more grunt, either will put a smile on your dial.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline mario medeiros

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Re: what did i buy? a 500 or 650?
« Reply #7 on: 17.10. 2013 00:15 »
So i now know i have a 650 top end any way of knowing what bottom end i have besides the #'s on the case?

Offline muskrat

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Re: what did i buy? a 500 or 650?
« Reply #8 on: 17.10. 2013 11:21 »
G'day Mario.
Highly unlikely to have a 500 crank. Rods and stroke are shorter so she wouldn't have enough compression to blow out a candle *eek*.
But then again another forum member got one like that and it did run *dunno2*.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline mario medeiros

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Re: what did i buy? a 500 or 650?
« Reply #9 on: 27.10. 2013 00:01 »
How is a bsa pre unit a10 titled? By the frame number or the motor number?Thanks

Offline muskrat

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Re: what did i buy? a 500 or 650?
« Reply #10 on: 27.10. 2013 00:17 »
G'day Mario, the engine # as all frames (bar the RGS) are stamped A7.
BUT an A7 crank, barrel, head, con rods, pistons and push rods can be put on A10 cases to make an A7.
To check what crank you have use a piece of wire down the plug hole to measure the stroke. 84mm for A10, 72.6mm for A7.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Online KiwiGF

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Re: what did i buy? a 500 or 650?
« Reply #11 on: 27.10. 2013 00:19 »
I recently found out the bsa despatch records are ordered by engine no so its hard for the vmcc uk who have the records to find out when a frame was despatched, its easy with engine numbef for them, but in terms of how registration is done it varies by country, in nz its a vin number attached to the frame, but years ago it was just frame no.
New Zealand

1956 A10 Golden Flash EA7-168x, CA10 913x, left BSA together for Liverpool, 5th Dec 1955.

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Offline Beezageezauk

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Re: what did i buy? a 500 or 650?
« Reply #12 on: 27.10. 2013 08:51 »
The UK BSA Owners' Club and the UK licensing authority (DVLA) both go by the frame numbers. 

In fact the BSAOC (UK) can issue a "Dating Certificate" that shows the model and colour of the bike, the actual date it left the factory and the dealership it went to.  These are inexpensive and are available to both members and non-members.

Beezageezauk.

Offline muskrat

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Re: what did i buy? a 500 or 650?
« Reply #13 on: 27.10. 2013 09:40 »
Same here, the VIN or frame # is the main identifier. So does that mean the only real A10's were RGS's *????*
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
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Online RichardL

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Re: what did i buy? a 500 or 650?
« Reply #14 on: 27.10. 2013 12:59 »
Bzgk,

Wrote an email with a simple question to the BSAOC librarian about a week ago and still waiting a reply. Hmm?

Richard L.
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