Author Topic: A7 plunger 1951, original air filtr box  (Read 417 times)

Offline Greybeard

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Re: A7 plunger 1951, original air filtr box
« Reply #15 on: 27.01. 2020 19:47 »
The correct air box has an oval aperture facing towards the oil tank, in front of the frame tube. The connector hose fits in here, then bends at a right angle to join to the carb.
Same sort of design as my A10 one.

Offline Simon59

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Re: A7 plunger 1951, original air filtr box
« Reply #16 on: 27.01. 2020 20:49 »
Here's a picture of the back of my airbox (same as Neil's - A10 plunger) together with the original Vokes air filter. Hope this helps?
Restoring a 1954 plunger framed A10 Golden Flash

Online trevinoz

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Re: A7 plunger 1951, original air filtr box
« Reply #17 on: 27.01. 2020 21:03 »
That is the early A7 fitting.

Online martinh

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Re: A7 plunger 1951, original air filtr box
« Reply #18 on: 27.01. 2020 21:36 »
I see it is for long stroke engine.
Thanks.

Offline S-O Skott

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Re: A7 plunger 1951, original air filtr box
« Reply #19 on: 30.01. 2020 14:20 »
Here you can find a complete airfilter with battery holder for sale

https://mikesclassiccyclespares.com/product/67-4594/


Offline Greybeard

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Re: A7 plunger 1951, original air filtr box
« Reply #20 on: 30.01. 2020 14:25 »
Here you can find a complete airfilter with battery holder for sale

https://mikesclassiccyclespares.com/product/67-4594/
It says 'Out of stock'
Also I notice this is not exactly the same shape as mine, so maybe that is for the early A7

Offline S-O Skott

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Re: A7 plunger 1951, original air filtr box
« Reply #21 on: 30.01. 2020 14:42 »
Sorry I didn't notice it was out of stock (I think I need new glasses)

BSA spareart book says spareart number 67-4597 and it looks like the one I have on my 1954 plunger, but I might be wrong.


Online Nourish

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Re: A7 plunger 1951, original air filtr box
« Reply #22 on: 03.02. 2020 15:00 »
Ok I can't see the difference - so please somebody tell me - What is the difference between the early and the later air filter?
Cheers

Offline Swarfcut

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Re: A7 plunger 1951, original air filtr box
« Reply #23 on: 03.02. 2020 16:42 »
Martin.  Additional detail concerning my earlier recommendations. It depends if you just want something that works, or true original parts to suit the model year.

 Airbox and filter element changed over time.

  1947 Rigid frame Longstroke A7 Engine  Air box battery carrier 67-4535,  Filter 67-4545.   Connecting hose 67-4546

   The connecting hose is straight and faces forwards towards the carb. Hole in airbox faces forwards.

  1947/48 appear to be the same basic parts.

  1949 Rigid      Frame to ZA7 109                      Airbox   67-4535         Filter    67-4545 ( 2 screw Fixing)

          Rigid      Frame ZA7 110 onward               Airbox   67-4558         Filter   67-4562  (3 Screw Fixing)

          Plunger...Same as Rigid ZA7110 on.         Airbox   67 -4558         Filter   67-4562.

  1949 models continue with the straight coupler 67-4546, from 1947. Airbox hole still faces forwards.
  The filter units look to be the same basic profile, detail difference being just the number of retaining screws.

  Can't tell if there is any significant difference, other than the number of screws but chewing this over makes me think your original airbox could be made to work.

   If the bike is a 1951 A7 Plunger, then the correct airbox with the outlet facing the oil tank is the one you want, which was introduced for the A10 in 1950.  This is the airbox and filter we are  more familiar with, requiring the rubber elbow hose.

         Airbox 67-4594    Filter 67-4600 (3 Screw Fixing)      Connector Hose A7  67-4596      A10  67-4589

   Fitted to Plunger Frames, also possibly to Rigids, the catalogues are somewhat vague at this changeover point.

       Nourish, All of the above gleaned by reference to Parts Catalogues, so apologies for not researching deeply enough previously before posting. Some of these variations were new to me.

 The answer to your question isn't here, but we can see some variations exist, position of air hose, screws securing filter element and possible variations in the profile of the pressing for the airbox.

 Errors and omissions? Someone check my part numbers please, I need a lie down!


 Swarfy.

 

                                                                     

   

Online Nourish

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Re: A7 plunger 1951, original air filtr box
« Reply #24 on: 04.02. 2020 07:52 »
Thanks Swarfy.

Online martinh

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Re: A7 plunger 1951, original air filtr box
« Reply #25 on: 05.02. 2020 12:31 »
Thanks a lot Swarfy for such detailed answer.
Martin

Offline Greybeard

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Re: A7 plunger 1951, original air filtr box
« Reply #26 on: 11.02. 2020 21:54 »
I found these nice pictures today while thumbing through the Haycraft BSA Twins book

Offline terryk

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Re: A7 plunger 1951, original air filtr box
« Reply #27 on: 12.02. 2020 08:44 »
I have a spare airbox and battery carrier for A10 A7 that I would sell send me a message. Im in Australia.
I thought I posted pics way back some years ago of the difference between longstroke and later airboxes.
1950-53 A10 rigid/plungers, 1958-61 A10 super rockets, 1947-50 A7 longstrokes, 1949 Star twin,
1951-54 A7 plungers, 1940s M21, WDM20s,
1948-50s B33s rigid/plunger/swingarm, 1948-50s b31s rigid/plunger/swingarm