'67 Atlas Air filter Assembly - info please

andyd · Mar 1, 2022

Good day all. Rebuilding a '67 Atlas and need help with the air filter. Bike has concentrics and I located a filter assembly that looks like it is for the concentric. I assumed the mount plate fitted over the carb body and was held by a commando type screw on ring but the plate will not fit over the carb body. How should the air filter be mounted to the carbs?
Assume there is also a sealing ring on the filter to carb mount?
Also have a pleated pape

'67 Atlas Air filter Assembly - info please

r air filter element but I think it

cannot fit in between the perforated parts of the filter assembly. It is the same width as the filter body.
Any pics appreciated.

drp · Mar 1, 2022

Unless you are really interested in a "correct" restoration I'd check out the K&N filter Colorado Norton Works sell for the for the cNw estart equipped Commandos. Somewhere along the line I managed to pick two narrow K&N's, one is new and the other used. The new one is on my 65 Atlas and fits great, the second one I will probably put on my Commando which I just put the estart on. The width on mine is about 1-3/4" at the filter end and I can only assume this is what cNw is selling for the estarts. I tried to fit the stock air filter on my Atlas and gave up, besides the stock element would only stock ciggie butts!
Dave

andyd · Mar 1, 2022

I have a couple of kn's for the commandos that would fit, but going for original, which was why I bought the air cleaner on ebay. But must be something missing somewhere.

robs ss · Mar 1, 2022

andyd said:
Good day all. Rebuilding a '67 Atlas and need help with the air filter. Bike has concentrics and I located a filter assembly that looks like it is for the concentric. I assumed the mount plate fitted over the carb body and was held by a commando type screw on ring but the plate will not fit over the carb body. How should the air filter be mounted to the carbs?
Assume there is also a sealing ring on the filter to carb mount?
Also have a pleated papeView attachment 85450r air filter element but I think it View attachment 85451cannot fit in between the perforated parts of the filter assembly. It is the same width as the filter body.
Any pics appreciated.

I have a similar filter for my 650ss and although not fitted yet I believe the smaller plate in your photos goes onto the carbs before the bellmouths and is actually clamped in place by the bellmouths.
The filter body is then held to that plate by the two screws.
Cheers

mean gene · Mar 1, 2022

This is my rat bike, rebuilt but no rust removed! It is mostly original. Carb plate goes on first then the threaded rings that hold plate to carbs. There is a thick black Oring, I used a thick yellow as seen in pics, between carb plate and filter housing. My filter has nothing more then window screen, no paper element.

andyd · Mar 1, 2022

robs ss said:
have a similar filter for my 650ss and although not fitted yet I believe the smaller plate in your photos goes onto the carbs before the bellmouths and is actually clamped in place by the bellmouths.
The filter body is then held to that plate by the two screws.

Ok all is clear. It looks like my assembly is for a smaller carb - maybe the 28mm carb has a smaller body. I can use part of a Commando inlet bellow for the sealing o-ring that fits on the air filter rear.

andyd · Mar 1, 2022

mean gene said:
View attachment 85458 View attachment 85460This is my rat bike, rebuilt but no rust removed! It is mostly original. Carb plate goes on first then the threaded rings that hold plate to carbs. There is a thick black Oring, I used a thick yellow as seen in pics, between carb plate and filter housing. My filter has nothing more then window screen, no paper element.

Thanks for the pics, appreciated.

robs ss · Mar 1, 2022

andyd said:
Ok all is clear. It looks like my assembly is for a smaller carb - maybe the 28mm carb has a smaller body. I can use part of a Commando inlet bellow for the sealing o-ring that fits on the air filter rear.

If you want that look then it's possible to enlarge the holes to suit
I have a friend who did just that for his Atlas.
I like @mean gene 's idea of the o-ring sealer. I'm pretty sure the originals had an air leak there.

Bodger · Mar 2, 2022

robs ss said:
If you want that look then it's possible to enlarge the holes to suit
I have a friend who did just that for his Atlas.
I like @mean gene 's idea of the o-ring sealer. I'm pretty sure the originals had an air leak there.

You have a repop filter housing. It does not have the original "holder" for the pleated filter. I will post pics of entire assembly later. You will have to rig something up with a piece of foam filter cut to fit. The order of assembly is: (1) mounting plate with two holes over carbs; (2)threaded rings on carbs to hold plate; (3) filter body over carb mouths. Should be rubber ring shaped liners on the entry holes to filter body to seal into carbs. Filter body then mounted to mounting plate with threaded studs welded to filter body that pass through holes on mounting plate. Use nuts to draw filter body towards mounting plate and then the rubber rings seal everything together. I will post pics later.

mdt-son · Mar 2, 2022

andyd said:
Good day all. Rebuilding a '67 Atlas and need help with the air filter. Bike has concentrics and I located a filter assembly that looks like it is for the concentric. I assumed the mount plate fitted over the carb body and was held by a commando type screw on ring but the plate will not fit over the carb body. How should the air filter be mounted to the carbs?

Your s/h air filter housing may be for the Amal Monobloc carbs which were fitted on the Atlas 1962-1966 (p/n 030337) It seems you are missing the side walls? The correct filter body for Concentric carbs is available from Norvil (p/n 033030).

- Knut

Bodger · Mar 2, 2022

I hope this is helpful. The first picture shows the interior of an original filter assembly. The crennelated (?) mesh behind the perforated metal holds the pleated paper in place. The rubber grommet (I called it a ring in my original post) seals the filter assembly to the carbs when all is bolted up. The bracket shown in the picture to the right is held on to the carbs by rings that thread on to the outside of the carb mouths. Norvil used to stock the rings but is out now. I suspect thathat the rings and grommets may be used on Commandos but I'm not an expert on modern (joking) bikes.

andyd · Mar 2, 2022

Bodger said:
I hope this is helpful. The first picture shows the interior of an original filter assembly. The crennelated (?) mesh behind the perforated metal holds the pleated paper in place. The rubber grommet (I called it a ring in my original post) seals the filter assembly to the carbs when all is bolted up. The bracket shown in the picture to the right is held on to the carbs by rings that thread on to the outside of the carb mouths. Norvil used to stock the rings but is out now. I suspect thathat the rings and grommets may be used on Commandos but I'm not an expert on modern (joking) bikes.

Certainly is.
I am now sure the filter assy I have is for a monoblock bike with smaller body carbs than the 30 mm concentrics. I can cut up old commando inlet bellows to mount on the body for the rubber grommet and enlarge the plate mount holes to fit the now 32m carbs and use a commando ring to attach the plate to the carbs. I will also add inner spacer tubes on the through bolts to stop deforming the end plates and seal the end plates probably with black silicon.
All sort of simple, but not as simple as the K&N option thats for sure - but if you want original that's the price you pay!
Thanks everyone.

robs ss · Mar 2, 2022

andyd said:
Certainly is.
I am now sure the filter assy I have is for a monoblock bike with smaller body carbs than the 30 mm concentrics. I can cut up old commando inlet bellows to mount on the body for the rubber grommet and enlarge the plate mount holes to fit the now 32m carbs and use a commando ring to attach the plate to the carbs. I will also add inner spacer tubes on the through bolts to stop deforming the end plates and seal the end plates probably with black silicon.
All sort of simple, but not as simple as the K&N option thats for sure - but if you want original that's the price you pay!
Thanks everyone.

One thing is certain - the distance between carb centres will be the same - so, if you're willing to "fettle" you'll get it to fit.
Cheers

marinatlas · Mar 3, 2022

Don't know if someone says that the spacers between carb and head are different from concentric (thin) and monobloc (thick ) ??

mean gene · Mar 11, 2022

Ebay has complete air cleaner for sale, most of all great pics!

robs ss · Mar 11, 2022

mean gene said:
Ebay has complete air cleaner for sale, most of all great pics!

Good - but not complete.
It's missing the plate that mounts it to the carbs (& screws)
Cheers

Stephen Hill · Mar 11, 2022

Over the years a good friend has made absolutely correct Atlas/650SS air filters for all the large British bike supply companies: CNW, British Cycle, etc. He is willing to make one offs for a reasonable price. If you are interested, and serious, let me know and I will pass along his contact info.

andyd · Mar 12, 2022

Stephen Hill said:
Over the years a good friend has made absolutely correct Atlas/650SS air filters for all the large British bike supply companies: CNW, British Cycle, etc. He is willing to make one offs for a reasonable price. If you are interested, and serious, let me know and I will pass along his contact info.

I assume Colin Kelly?
But I now have the unit found on Ebay that will be fine after a bit of work.

Elfix · Feb 13, 2023

I have found its easy to cut a piece of Uni filter media to sandwich in between the outer and inner portion of the housing. This filters very well and didn’t appear to cause any restriction issues

Elfix · Feb 13, 2023

Ive also made a hammer form to make new copies of the endplates- if anyone needs a set let me know.

'67 Atlas Air filter Assembly - info please

andyd

drp

andyd

robs ss

mean gene

andyd

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Bodger

mdt-son

Bodger

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