Alternate Air Filter

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eo1bart

eo1bart

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I am finishing up the rebuild on the '74 Mk2 Commando that I bought last year, and have a question regarding the air filter.
The bike did not come with the "ham can" air filter set up, instead it has a K&N universal filter (R-0090).

I have no intention of going back to the stock setup due to the difficulty with removal/install, but I've discovered that the K&N is also a very tight fit due to its width.

The narrow K&N at CNW seems to be just what I need but they are currently unavailable.
https://coloradonortonworks.net/k-n-narrow-air-filter-for-amals.html

So my question is, what are the other options for a filter that is easily removed? I can't find any.
 
eo1bart said:
I am finishing up the rebuild on the '74 Mk2 Commando that I bought last year, and have a question regarding the air filter.
The bike did not come with the "ham can" air filter set up, instead it has a K&N universal filter (R-0090).

I have no intention of going back to the stock setup due to the difficulty with removal/install, but I've discovered that the K&N is also a very tight fit due to its width.

The narrow K&N at CNW seems to be just what I need but they are currently unavailable.
https://coloradonortonworks.net/k-n-narrow-air-filter-for-amals.html

So my question is, what are the other options for a filter that is easily removed? I can't find any.
Click to expand...
Ask Matt how soon to expect them. I used the wider one for a long time and it is a bitch to install them but once on work fine.If you want it to use in the interim,get in touch and I will send it to you
Mike
 
Take a look at the commando filter from MAP cycles. It flows better than the K&N and the flange is sloped to allow for easier removal/refit
 
acadian said:
Take a look at the commando filter from MAP cycles. It flows better than the K&N and the flange is sloped to allow for easier removal/refit
Click to expand...
The MAP filter looks identical to the K&N I have, and based on the dimensions listed is not more narrow.
 
I now use the newer low profile K&N with great joy and ease of install/removal as the previous "taller" version was a major PITA to install or remove.

To make the process of removing or installing the tall version a bit easier I measured the throat length of the filter (female side) and compared that measurement against the length of the air intake ports on the Amal.
Using that difference in length I wrapped a clamp/hose fitting around the rubber "female" side of the filter fitting as a guide and removed material (exacto knife) while still keeping enough material in place to clamp it to the carb intake throat.

It did not make a huge difference in install or removal but even a small concession helps in getting that filter mounted or pulled.
 
Last edited:
My ‘72 ham can front and back plate are smooth on the inside. Some of the 850 front plates have a funnel on the inside for air flow. The smooth type can use K&N NO-100 which is a normal Commando size. The K&N can be muscled into place without breaking. The stock paper filter will break if you try this.
 
illf8ed said:
My ‘72 ham can front and back plate are smooth on the inside. Some of the 850 front plates have a funnel on the inside for air flow. The smooth type can use K&N NO-100 which is a normal Commando size. The K&N can be muscled into place without breaking. The stock paper filter will break if you try this.
Click to expand...
Yes I run that stock sized K&N between ham can plates. It is not hard to fit at all really, b/c you and flex it and let it sort of roll into place as needed. Bigger fiddle is getting the rubbers sorted onto carb opening, but again not too bad if using a long thing blade screw driver to lever the lips over the openings. Generally I leave the steel grille off the hamcan since i've been having to go back into carb quite often, but may now be done with fettling so might put it back on soon, just for the looks.
 
YING said:
Ask Matt how soon to expect them. I used the wider one for a long time and it is a bitch to install them but once on work fine.If you want it to use in the interim,get in touch and I will send it to you
Mike
Click to expand...
I'm waiting on one also, my understanding is that they are a special run from K&N so we're probably at their mercy.
 
Tornado said:
Yes I run that stock sized K&N between ham can plates. It is not hard to fit at all really, b/c you and flex it and let it sort of roll into place as needed. Bigger fiddle is getting the rubbers sorted onto carb opening, but again not too bad if using a long thing blade screw driver to lever the lips over the openings. Generally I leave the steel grille off the hamcan since i've been having to go back into carb quite often, but may now be done with fettling so might put it back on soon, just for the looks.
Click to expand...
I chrome plated my perforated surround and the front plate. It looks like an air cleaner from late 60s muscle car.
 
eo1bart said:
I am finishing up the rebuild on the '74 Mk2 Commando that I bought last year, and have a question regarding the air filter.
The bike did not come with the "ham can" air filter set up, instead it has a K&N universal filter (R-0090).

I have no intention of going back to the stock setup due to the difficulty with removal/install, but I've discovered that the K&N is also a very tight fit due to its width.

The narrow K&N at CNW seems to be just what I need but they are currently unavailable.
https://coloradonortonworks.net/k-n-narrow-air-filter-for-amals.html

So my question is, what are the other options for a filter that is easily removed? I can't find any.
Click to expand...
Contact Greg Marsh.
 
A question for those of you that are using the K&N R-0090 air filter on your pre-MK3 Commando. I'm helping a friend install a CNW starter and have had to remove the stock air filter, and switch to the K&N. We've retained the stock rear air filter cover, as it has the ignition switch bracket attached. There is a hose attached to the back of the cover which connects to a fitting at the front top of the oil tank. I imagine that fumes or mist from the oil tank are meant to be inhaled by the carburetors via this hose. I fear if left as is, oil mist will flow down the hose from the tank, collect on the inside of the back plate, and make a mess.
Would be grateful for any info from anyone who has successfully dealt with this, or please advise if it is even an issue ? Thanks !
 
You could fit a catch can of some sort, maybe extend hose or route straight off the tank pipe to a discreet location. I've seen many a vintage bike with a tank breather line routed rearward along mudguard and as far back as possible to drip out behind tire. Another idea would be to feed it to the chain oiler line if you kept that.
 
Mike In Mass said:
A question for those of you that are using the K&N R-0090 air filter on your pre-MK3 Commando. I'm helping a friend install a CNW starter and have had to remove the stock air filter, and switch to the K&N. We've retained the stock rear air filter cover, as it has the ignition switch bracket attached. There is a hose attached to the back of the cover which connects to a fitting at the front top of the oil tank. I imagine that fumes or mist from the oil tank are meant to be inhaled by the carburetors via this hose. I fear if left as is, oil mist will flow down the hose from the tank, collect on the inside of the back plate, and make a mess.
Would be grateful for any info from anyone who has successfully dealt with this, or please advise if it is even an issue ? Thanks !
Click to expand...
I have recently install a K&N on my MK2 Commando and attached the hose to back of the cover as you stated. So far I've gone approx. 100 miles with no signs of oil from the hose.
 
I took the back plate of and made a small plate out of stainless and use the big K&N filter even with rubber mount carbs plenty of room to get the filter on and off
 

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eo1bart said:
I have recently install a K&N on my MK2 Commando and attached the hose to back of the cover as you stated. So far I've gone approx. 100 miles with no signs of oil from the hose.
Click to expand...
Bart,
Here is what I used for the same bike with the CNW starter
 

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YING said:
Bart,
Here is what I used for the same bike with the CNW starter
Click to expand...
Ying, I take it the small round filter is what you're referring to? Can you tell me where you bought it, what it's original application was? And what is the brass implement the large oil hose is attached to? Thank you !
 
phippsy said:
I took the back plate of and made a small plate out of stainless and use the big K&N filter even with rubber mount carbs plenty of room to get the filter on and off
Click to expand...
This is an excellent suggestion, and the way I would like to go, but my friend prefers to retain the back plate.
 
Mike In Mass said:
Ying, I take it the small round filter is what you're referring to? Can you tell me where you bought it, what it's original application was? And what is the brass implement the large oil hose is attached to? Thank you !
Click to expand...
Seems to be a standard K&N crankcase breather filter common on car setups. It will give off light mist of oil vapour (my large oem style k&n in hamcan airbox does this at idle, hard to see unless sunlit just right and no wind, looks like light smoke).
Any vapour will leave oil build up as it cools on surfaces. I'd expect a puddle of oil in the hose if it is the lowest point before filter. That's why a catch can is used in many bikes/cars.
My modern Triumph has a short bit of tubing off bottom of airbox to accumulate this condensed oil vapour. Tube is sealed off at bottom end. Supposed to remove, drain and replace at regular intervals. Hardly anyone ever does it. No harm comes.
 
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