Author Topic: cylinder head identification  (Read 2225 times)

Offline lefty

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cylinder head identification
« on: 03.02. 2009 06:51 »
hi all,

i thought of one more question i needed to ask....my cylinder head has 67-1062 cast in it. My parts book says 67-1061 is correct for my 61 A7. i thought the casting numbers were usually lower than the finished product???? this was an ebay replacement for the A10 head the project came with! from memory, the intake bore is what it should be, but i want to be certain before i spend the cash rebuilding it and having a broken fin welded back on.

if anyone ever comes across a list of bsa casting numbers i'd love to see it

thanks
leif

Offline fido

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Re: cylinder head identification
« Reply #1 on: 03.02. 2009 12:38 »
Don't know if this helps:
http://atlanticgreen.com/a10dph.htm

Offline lefty

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Re: cylinder head identification
« Reply #2 on: 04.02. 2009 15:54 »
i found a little more info... apparently the A7 ST from 1951 to 1954 used cylinder head number 67-1063. Perhaps this could be it? Damn casting numbers!  the heads look the same except the ST should have a 1" bore rather than 15/16". if it is a ST head it then shares part numbers for the valves and guides with the SS models despite the springs being the same length, as is the bore, compression, etc.  that said, the 61 A7 has a longer stroke, but this would only matter to the barrel length wouldn't it? would the performance be hindered/improved by using this head if a carb can be jetted to suit?

i will measure it's inlet today and confirm one way or the other....

would there be any other obvious ways to tell if it's suitable ???

thanks
leif

Offline beezalex

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Re: cylinder head identification
« Reply #3 on: 04.02. 2009 18:32 »
leif, your (67-1063) head was not introduced until '54 and is for the same bore and stroke (66 X 72.6) as your '61.  It came out at the same time and mounts to the same barrel as 67-1061.  I would not be surprised if both heads used the same casting, but the ST was simply machined differently.  15/16 BTW should be correct for your application, so you may, in fact, have the correct head.  This would make sense to me since standard A7 heads seem to be plentiful, but I have yet to see an ST head.

Let me go dig up my standard A7 head and see what the casting number on it is.

Cheers.
Alex

Too many BSA's


Offline lefty

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Re: cylinder head identification
« Reply #4 on: 05.02. 2009 00:41 »
thanks, i appreciate you checking....fingers crossed for 67-1062......!
leif

Offline beezalex

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Re: cylinder head identification
« Reply #5 on: 07.02. 2009 19:34 »
Hey Lefty, I checked the head that I have, which is tagged with "59 A7".  The casting number on it is 67-1062.  The inlet is 15/16".  I think you're set as far as the head goes.
Alex

Too many BSA's


Offline lefty

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Re: cylinder head identification
« Reply #6 on: 08.02. 2009 02:48 »
thanks so much for checking on that,
after almost spending the money doing up an a10 head the first time, i've learned that this project might have had a few incorrect items gathered with it....now with a little caution, things should slowly start coming together.

regards,

leif