Author Topic: A7SS Correct Valve info  (Read 943 times)

Offline Terryb

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A7SS Correct Valve info
« on: 22.12. 2016 18:42 »
Can any body Help?

I have a 1955 A7SS (engine no.2367) and I'm trying to get the correct replacement valves to replace a mixed bag of pick and mix valves. The existing valves in the head at the moment are 67-741 on the inlet side and a V15 and V16 on the exhaust side.

One source tells me they should be 67-394 (IN) and 67-395 (EX) another tells me 67-531 (IN) and 67-532 (EX)

Does anybody know the correct numbers?

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Re: A7SS Correct Valve info
« Reply #1 on: 22.12. 2016 19:02 »
G'day Terry.
67-531 & 67-532 for the alloy head A7SS.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

beezermacc

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Re: A7SS Correct Valve info
« Reply #2 on: 22.12. 2016 22:24 »
According to my information there are three part numbers for the inlet valves, 67-394 / 531 / 740. Alpha (UK) list one inlet valve for the full range of A7 and A7SS which is V15 and measures 1.315". I don't know why the BSA part number changed. There is exactly the same scenario for the exhaust valves; BSA numbers 67-395 / 532 / 741, Alpha V16, 1.285".

Offline Terryb

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Re: A7SS Correct Valve info
« Reply #3 on: 23.12. 2016 10:27 »
OK thanks guy's, but the plot thickens. I've just checked and the Cylinder Head part number is stamped 67-1106, is this an A7 or A10 Head, any one know?


Online bsa-bill

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Re: A7SS Correct Valve info
« Reply #4 on: 23.12. 2016 10:57 »
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

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Re: A7SS Correct Valve info
« Reply #5 on: 23.12. 2016 19:23 »
G'day Terry.
 "The valves were 1958/59 super rocket, intake #67-968-1.41", exhaust #67-967-1.38"."
I just fitted these valves to my 1102 head but I had to use the A7SS springs and collar with the SR collets.
Cheers
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Offline Terryb

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Re: A7SS Correct Valve info
« Reply #6 on: 28.12. 2016 09:54 »
OK Guy's thanks for the advice on the valves, next question:

Head gasket - Looking at the parts book 1954-57 edition for 500cc and 650cc bikes, the part number for 'A' Group (Plunger and Swinging Arm Frames) is 67-255. I can not find any other numbers for a 1955 A7SS, so am I to assume that this gasket fits both A7's and A10's?

Online Greybeard

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Re: A7SS Correct Valve info
« Reply #7 on: 28.12. 2016 11:27 »
OK Guy's thanks for the advice on the valves, next question:

Head gasket - Looking at the parts book 1954-57 edition for 500cc and 650cc bikes, the part number for 'A' Group (Plunger and Swinging Arm Frames) is 67-255. I can not find any other numbers for a 1955 A7SS, so am I to assume that this gasket fits both A7's and A10's?

You should start a new thread for this question. Makes it easier to search for later.

Online RichardL

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Re: A7SS Correct Valve info
« Reply #8 on: 04.03. 2021 02:00 »
According to my information there are three part numbers for the inlet valves, 67-394 / 531 / 740. Alpha (UK) list one inlet valve for the full range of A7 and A7SS which is V15 and measures 1.315". I don't know why the BSA part number changed. There is exactly the same scenario for the exhaust valves; BSA numbers 67-395 / 532 / 741, Alpha V16, 1.285".

I think I found the right old topic and the right revered member to quote.

So, A7'ers, I'm sure one among you has been dying to answer this very question. (Granted, it does not involve Audi's or Ariel's, but still involves "A"s.) Last week I ordered new exhaust valves for my '57 A7 Twin (not A7SS). My parts book says I need 67-0395 and that's what I thought I ordered (at a very good price) from a reputable stateside dealer. What I got was 67-0741. Beezermac seems to be saying they are the same, and they almost are.  They appear to differ only by the length and shape of the recess for the cone-shaped retainers.  In the picture below, you can see that the 67-0741 has a slightly longer recess with the end toward the valve head more radiused. Does anyone know if these are fundamentally wrong, OR, require different retainers, OR, should work fine with the retainers for 67-0395.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Online RDfella

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Re: A7SS Correct Valve info
« Reply #9 on: 04.03. 2021 10:48 »
Looking at it from an automotive point of view (ie not A7 specific) I'd say the radius at the bottom can do no harm - helps to reduce the possibility of failure. The fact the slot is longer should make no difference, as it's at the base of the collets, whilst they seat at the top. There has to be some clearance, and unless it was manifestly excessive, can't see how that would deleteriously affect things. Just my 2 cent's worth...
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Re: A7SS Correct Valve info
« Reply #10 on: 04.03. 2021 11:16 »
just to point out that the A7 exhaust valves I have at hand are 67-0395 and have the LONGER collet recess not the short and stepped one, I also have made in England V15 inlets with the long recess and made in England V16 exhausts with longer recess that were fitted in my ally head, this makes no difference except it's a little bit easier to fit the collets . just looked in a 1954 to 1957 parts book and the exhaust valve in that for the SS is 67-0532 and in ink I have written 67-0741 and put a note which says same valve. the shop owner at gaggs of Nottingham told me this in the 80's. there is also a note next to the inlet that is printed 67-0531 and my writing 67-0740 same inlet valve. these are listed as A7 SS ..The plunger and swing arm A's are listed as , inlet 67-394 and exhaust 67-395 so as far as I can see I have had early inlet and exhaust valves in my ss years ago and basically they made no difference . the only confusion being Richards 67-0395 have short recess and mine has the longer recess

Online Radlan2

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Re: A7SS Correct Valve info
« Reply #11 on: 04.03. 2021 11:49 »
Hi Terry
     I have found a difference between factory valves is in the hardness of the tips, some become indented and some are hardened. In order to refresh used valves I have fitted lash caps and have shortened the tip to both clean up the face and keep the geometry reasonable. Some tips are really tough with others readily machineable. Perhaps the earlier valves were a bit too soft?
                    Chris

Online JulianS

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Re: A7SS Correct Valve info
« Reply #12 on: 04.03. 2021 20:30 »
Below from the 1963 Alpha catalogue.

Online RichardL

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Re: A7SS Correct Valve info
« Reply #13 on: 05.03. 2021 03:08 »
Julian,

Thanks. It's very interesting that '56-'62 starts at engine number CA7-5001, but my '57 is about 600 engines earlier than that. Dispatch papers put engine and frame as a '57 leaving the factory together. I think I must have the original valves and iron head. The valves are stamped with what must be original factory numbers of "67-395," "EX" and piled arms, but 395 is listed as only going through '55.  I wonder if they found a bunch or earlier engines in storage and threw them in '57 frames.

Richard L.
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Re: A7SS Correct Valve info
« Reply #14 on: 05.03. 2021 10:23 »
they may well have been changed over the years?