The BSA A7-A10 Forum

Technical => Frame => Topic started by: Richard A on 25.04. 2018 16:30

Title: A7 Plunger air filter box
Post by: Richard A on 25.04. 2018 16:30
Some of you may recall a long thread re trying to find a replacement air filter box for my 1952 A7 ST. After many false starts I had the extremely generous offer of the loan of a complete box from someone on this forum. This loan came with no strings attached and allowed me to find a local welder/fabricator who managed to make me a new one from scratch.
The replacement air filter had to come from Aus though, but I now have a complete air filter ready to fit to the bike.
Huge thanks to the generosity of all those who contribute to these pages!

Title: Re: A7 Plunger air filter box
Post by: Greybeard on 25.04. 2018 17:51
Some of you may recall a long thread re trying to find a replacement air filter box for my 1952 A7 ST. After many false starts I had the extremely generous offer of the loan of a complete box from someone on this forum. This loan came with no strings attached and allowed me to find a local welder/fabricator who managed to make me a new one from scratch.
The replacement air filter had to come from Aus though, but I now have a complete air filter ready to fit to the bike.
Huge thanks to the generosity of all those who contribute to these pages!

Wow, that's great news. May I see a picture of the box please. It might be possible to cover your costs by getting more of those made up and flogging them; they are rare and in demand.
Title: Re: A7 Plunger air filter box
Post by: Richard A on 25.04. 2018 20:42
Hi, would be happy to load a picture, but my photos are just too big at 2.2mb and I cant work out how to reduce size on Apple.
Title: Re: A7 Plunger air filter box
Post by: Richard A on 25.04. 2018 20:52
Hopefully photo now attached
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 26.04. 2018 08:43
Will you show the other side please
Title: Re: A7 Plunger air filter box
Post by: muskrat on 26.04. 2018 08:50
Good one Richard. I can see why your pics are too big. You put it in twice.  *whistle*
Cheers
Title: Re: A7 Plunger air filter box
Post by: Richard A on 26.04. 2018 10:58
Further view as requested, hopefully only one copy this time!
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 26.04. 2018 19:21
Other side please  *smile*
Title: Re: A7 Plunger air filter box
Post by: Sluggo on 26.04. 2018 19:32
I too would like to see more pictures, perhaps lay a few tape measures (Extended) along side for scale as well.
Its hard to tell what I am looking at.  However, That squarish filter in some of the pictures sure looks like a 71-73 BSA & Triumph OIF 650 air filter element which would be an interesting and clever idea as those are readily availible for a wide variety of vendors.  Am I to understand that is to be used as a filter element for this A10?
Title: Re: A7 Plunger air filter box
Post by: muskrat on 26.04. 2018 20:44
I think you might be right Sluggo. There was a topic a while back on making/finding a replacement for the old Volks filter.
Thanks for posting this Richard. is Sluggo right?
Cheers
Title: Re: A7 Plunger air filter box
Post by: Richard A on 27.04. 2018 12:36
Gents, another photo for you, the original alongside the shiny metal new one.
As to the filter and cover I spotted an advert on this forum from a guy in Australia saying he'd made some new ones. This to include the filter, so not sure where it originated from, but it fits the filter box well.
For your next question then the box was not English rolled in making as just way too expensive, so sorry if it upsets the purists, but sides were welded to the base and molded to fit, but it got the job done and looks just as good.
Hope this answers your queries guys.
Richard

mod edit remove pdf replace with jpeg
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 27.04. 2018 13:15
Sorry to nag but I'd like to see the other side :)
Title: Re: A7 Plunger air filter box
Post by: Richard A on 27.04. 2018 17:58
Greybeard, not sure why you're keen to see the reverse side , but here you go.
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 27.04. 2018 18:12
Greybeard, not sure why you're keen to see the reverse side , but here you go.

Thanks. Is there a chance of getting your chap to make more of them?
Title: Re: A7 Plunger air filter box
Post by: Richard A on 27.04. 2018 18:28
Hi, I can ask, but I very much doubt it.
He is now working on my fuel tank which has shown significant rust problems.
Suggest you try a fabricator in your area if you have an existing filter box to use as a template. If you stay away from the English rolling and go as I went then much more chance of getting someone to do the dead.
As a price guide then think £300+. I know that sounds expensive, but there no alternatives out there as I'm sure you know.
Richard
Title: Re: A7 Plunger air filter box
Post by: Sluggo on 28.04. 2018 06:58
Greybeard, not sure why you're keen to see the reverse side , but here you go.

Becauses its a useful resource. 
A) A person can ID what a proper one looks like if you have sample to look at, or run across one for sale (Or hanging up in a garage somewhere
B) it gives useful reference material if you have or find one thats damaged, missing parts or modified
C) a clever lad can fab or make their own IE: Copy/reverse engineer.   Might not be the exact same or even a 1 off custom but at least you have a reference point as "This is original/stock" and can go from there.

In the Air Force they were very strict on Aircraft and munitions/weapons that *IF* you followed the "Technical Order" or TO which was basically the workshop manual then you were covered and competent.

(Not doing so could result in Court Martial or getting someone killed/maimed so always good to follow the rules.)

However, as well know using workshop manuals, SOMETIMES its just not 100% clear exactly what you are doing.  So, on the flightline we had a slang-derogatory term I will skip naming, But it was basically go consult one of the other acft or systems on the flightline.  Wing: 20 acft, sometimes 12 Squadron 24.
If you got called out or questioned it was simple enough to defend your decisions that the other acft were operational with the same wiring arrangment, or alignment, or which side the spacer fits.

Which is a long way to say, we dont have a fleet of similar vehicles to compare with, so good photos are a godsend when sitting in a shed in Armpit Oklahoma, Or MooseJaw Canada and havent the faintest idea what the part looks like.

As to the fab, excellent job, The original was formed either on a Buck, or stamped on a Die for the body, Totally acceptable how your fab guy constructed it.
 **Its an airbox fer christs sake, not the gyro for the Mars rover**

Since your fab source is not interested in commercial volume, whats the chance of making templates-tracings of the parts and posting them?  All the parts can be made from flat sheet stock and then welded and bent/formed.  If you have an original, the fab guy is very unlikely to just free form winged it, clearly made construction paper/cardboard/hardy board templates.
I know from classes and prev fab, that when making templates you have to allow for shrinkage and growth when bending/forming.
When we did classes in fabbing gas tanks and metal forming, some fab guys wont allow others to copy their work, some willing do so.
Given the lack of resources, those who share such material are doing the vintage community and great service
Title: Re: A7 Plunger air filter box
Post by: duTch on 28.04. 2018 09:07

 
Quote
....so good photos are a godsend when sitting in a shed in Armpit Oklahoma, Or MooseJaw Canada and havent the faintest idea what the part looks like.........
                               ...................or even in Armoury Lane, Birmingham ... *smile*
 
 
Quote
.... **Its an airbox fer christs sake, not the gyro for the Mars rover**......
it's not *????*

     *eek*....I think a bubble just blew(out) *smile*
Title: Re: A7 Plunger air filter box
Post by: Roadhog on 06.05. 2018 17:05
Hi Richard A. what is the filter you are using in the box, thanks
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 06.05. 2018 18:05
Hi Richard A. what is the filter you are using in the box, thanks
I used a K&N filter designed for the Triumph triples. https://www.knfilters.co.uk/search/product.aspx?prod=tb-0300

I cut out the part that I could use and attached it to the filter holding part with cable ties, as per photos. You can get two filters from the original. You should never need another one so you could flog the other half to another Plunger owner.
Title: Re: A7 Plunger air filter box
Post by: Roadhog on 06.05. 2018 18:31
What a great idea, thanks for that.
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 06.05. 2018 22:00
What a great idea, thanks for that.
It wasn't my idea originally. I think maybe someone here may have suggested it.
Title: Re: A7 Plunger air filter box
Post by: Ted_Flash on 07.05. 2018 08:15
Early Ford Fiesta filters also work.  They are about a foot in diameter and I used to get three A10 filters from the one Ford. Probably cheaper than K&Ns.
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 07.05. 2018 08:28
Early Ford Fiesta filters also work.  They are about a foot in diameter and I used to get three A10 filters from the one Ford. Probably cheaper than K&Ns.
The K&N filters are not cheap but you don't need to ever change them; you wash them then apply a special K&N fluid to dampen them.
Title: Re: A7 Plunger air filter box
Post by: Sluggo on 07.05. 2018 08:52
Early Ford Fiesta filters also work.  They are about a foot in diameter and I used to get three A10 filters from the one Ford. Probably cheaper than K&Ns.
The K&N filters are not cheap but you don't need to ever change them; you wash them then apply a special K&N fluid to dampen them.

I second that K&Ns are a good option.  I use them on many makes and model vehicles ( 2 & 4 wheel) as well as got a pile of them from a shop clean out I bought so sometimes repurpose them for other applications similar to the above shown here.
Invariably on many forums someone will post a link or repost of all sorts of dire things that will happen if you use them.  I started using them in the 1980s including a stint racing and no evidence IMHO.
Proper service, cleaning and reoiling and Bobs a close relative.  *IF* you are in a high dust environment or extreme service applications a "Prefilter" is the solution.
K&N makes proprietary ones, But working as a Millwright & Maint dept changed a lot of what is called
"Hepafilters" which is a commercially made roll of filter material for many different apps and I cut off and saved the trimmings and make my own prefilters.  Cut to width & length and a bit of epoxy and velcro you can have a nice "Sock" prefilter if you need it.

K&Ns in testing actually flow and filter best when just a tad dirty.  Too clean and fresh oiling they dont filter as finely as some others.  But just a little bit of use they actually improve.  FYI.
On many of my applications its the last filter I will ever buy, which has value to me.  1 & done.
Title: Re: A7 Plunger air filter box
Post by: Simon59 on 07.05. 2018 12:32
So with the filter sorted, (thanks guys) does anyone know where to get the rubber connector from an Amal 276 to the filter box?  *conf*
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 07.05. 2018 13:26
So with the filter sorted, (thanks guys) does anyone know where to get the rubber connector from an Amal 276 to the filter box?  *conf*
https://www.ebay.co.uk/itm/BSA-A7-AIR-FILTER-INTAKE-HOSE-BOOT-RUBBER-67-4596/261982316224?hash=item3cff5ce6c0:g:ZmsAAOSwT6pVjBEd
https://www.ebay.co.uk/itm/BSA-A10-650-Pre-Unit-Carb-Air-Filter-Connector-Rubber-67-4589/162982834945?hash=item25f288b301:g:0iQAAOSw73NaxiOx

Those ones do not show a springy retaining thing as my one did. You can see it in those pictures of my filter etc.

Title: Re: A7 Plunger air filter box
Post by: Richard A on 07.05. 2018 17:38
Folks,
hopefully pic of the old filter box the was fitted on the bike when I got it. I know that its not the correct one, but does anyone know who model it fits? Definitely matches all 3 plunger mounting point. I can only guess what it might fit.
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 07.05. 2018 17:55
I know the A7 filter is different to the A10 one. Is that a standard A7 filter box?
Title: Re: A7 Plunger air filter box
Post by: muskrat on 07.05. 2018 20:04
The rubber connector is different A7 to A10 due to the taller barrels of the A10. The filter housing/battery carrier are the same.
Cheers
Title: Re: A7 Plunger air filter box
Post by: Greybeard on 07.05. 2018 20:10
The rubber connector is different A7 to A10 due to the taller barrels of the A10. The filter housing/battery carrier are the same.
I believe you already told me that a while ago. Sorry!
Title: Re: A7 Plunger air filter box
Post by: trevinoz on 07.05. 2018 22:40
Looks like a battered example of the early long stroke set-up.
Title: Re: A7 Plunger air filter box
Post by: Richard A on 08.05. 2018 13:55
Thanks for that. Its only slightly bent around the rubber connector fitting, the rest is in good order and even has a new filter fitted.
Anyone know if these are worth anything and if so how much as I'd far rather it got used then just sitting in the shed and unloved!