Author Topic: How to clean Foam Filters  (Read 1326 times)


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How to clean Foam Filters
« on: August 13, 2005, 06:52:18 AM »
Just a little FYI for cleaning foam filters.
Most people over oil them and/or use the wrong type of oil.

This is a summary of an old article I read in Motocross Action a long time ago - it covered cleaning and oiling of foam filters.

1) Cleaning foam air filters:
First and most importantly, DO NOT use gasoline to clean your filters.  It eats the glue that holds them together and it's not good for the foam.  Use a foam filter cleaner.

Do NOT wring the filter or twist it like you would a rag trying to get all the water out.  Twisting's bad for the material.

Last, but not least, is to work from the inside of the filter outward.  They suck dirt from the outside in, so you want to work the dirt the opposite direction it came in, not work it farther into the filter.

Get an air filter cleaning solution.  K&N makes a killer product. (it's also great for removing stains from clothing).  There are probably half a dozen good cleaners available, I'm just partial to K&N's...  I've heard some people say Simple Green works well too. (I don't know about this one, though)

Take a soft bristle brush (like a dish brush) and gently brush away the crusties and the majority of the dirt on the outside of the filter.  Don't go nuts and try to scrub it clean, just get the big stuff and surface scum off.

Spray the cleaner on the filter until it's completely covered both inside and outside.  Let the filter sit for a couple minutes and then work the cleaner in (don't twist!).  Now wash the filter from the inside with the hottest water your hands can stand.

Fill your hands with a generous amount of dish soap and work this into the filter.  Remember to try to work from the inside outward.  Once you get it all nice and foamy, rinse from the inside out again with hot water.  You'll be able to see when the water starts running nice and clear.

Squeeze as much of the water out of the filter as you can get.  I start at the top and work the water down and out.  Don't Twist!

Set it on a clean surface and let it dry completely.  If you feel you have to use compressed air to blow a bit more of the moisture out, make sure you blow from the inside of the filter outward.  Don't get carried away and blow holes in the foam either.  Remember, gentle is best on foam.

2) Oiling your filter.
You need four things:  Filter oil, BIG baggie, latex (or similar) gloves & paper towels.

This is where a lot of people go wrong...   Do NOT use motor oil.  It will migrate to the bottom of the filter and it doesn't have any "sticky" properties.  It's not filter oil, it's motor oil - says so right on the label...

Foam filter oil is designed so that it has a carrier that allows it to spread through out the filter and then the carrier evaporates, leaving a sticky oil.  The sticky oil won't migrate and it is designed to capture the small dust particles and hold them in the filter, not let them slide on through (as does motor oil - to a point)

There are two types of filter oil:  Pour on and Spray on.

For pour on, take the clean foam filter and put it in a big baggie.
Pour a generous amount of FOAM FILTER OIL (NOT motor oil) into the baggie - all over the filter.

If you use spray on oil, saturate the filter, both inside and out and then put it in the big baggie.

Close the baggie except for about 1/4" and then squeeze the majority of the air out of the baggie.  Zip it shut.

Work the oil through the filter while it's in the baggie.  Work it through the filter the best you can and then work the filter up to one corner of the baggie. (the zipper corner is best)

Starting at this corner, squeeze as much of the oil out of the filter as possible (like you did when you worked the excess water out of the filter) Don't twist/wring the filter, just keep squeezing and working it to the opposite corner.  The excess oil will go to the bottom of the baggie where you can collect it and put it back in the container it came from.

Put on your gloves and remove the filter from the baggie - try to keep it from getting in the excess oil in the bottom of the baggie.

Take the filter lay it down on some clean paper towels.  Gently press the filter between a couple more paper towels to get the "wet residue" off (you're not trying to remove all the oil, just get the wet off) and then let the filter sit for about 30 minutes so the oil carrier can evaporate.

Install the filter and away you go.

Remember, the key elements
1) Clean from from the inside out
2) Do NOT use gasoline
3) Do NOT wring/twist
4) Use FILTER oil
5) Don't over oil
and, of course, ENJOY THE RIDE!

I usually do my filter cleanings in groups.  If you have a couple spares, wait until they are all dirty and then do the nasty clean job all in one shot. - while stuff's drying, go check fuel filters, change oil, muck about and check your ride.
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'