Air Filters


11 replies to this topic
  • PatrickM

Posted January 29, 2008 - 01:15 AM

#1

I just purchased myself a new a new Twin Air Air Filter for my 1999 YZ400F and It looks to be dry (no oil on it).


I know that the best filters work when they are oily. I thought that all air filters came pre-oiled.


Since this Filter is not oiled....What do I need to oil it and seal it to the air box?


Thanks for the help!!!!


Patrick M.

  • stroker101

Posted January 29, 2008 - 03:49 AM

#2

visit your local bike shop and purchase "foam filter" treatment oil. there are several brands to choose from and all are good at filtering dust and dirt.
be sure to follow the instructions. you can use a small amount of grease on the filter mating surface where it contacts the filter box if you like. some use this method for the extra protection. i choose to add more filter oil to this area.

  • grayracer513

Posted January 29, 2008 - 07:38 AM

#3

Not only are they not oiled, for the most part, they should be washed out and re-oiled no less than every third ride, and often warrant cleaning every ride here in CA. If you ride exclusively in front of the pack in a damp, dust free environment, you can extend this interval some, but you don't, do you?

Foam and gauze (like K&N) filters not only work better when oiled, the fact is that they don't work at all when they aren't. Oh, they'll keep stones and larger spiders out of the intake, but that's it. The thing that makes them high performance is the large passages in the foam, which allow air to flow very freely into the filter. It is the oil that does the filtering. The airways in the filter are not straight. They weave back and forth, forcing the air to twist and turn, and flow around the webbing of the foam. The dirt, being much heavier, fails to follow these maneuvers very well, and runs into the foam as the air veers around it. If the foam is oily, the dirt gets stuck, and the air is filtered. This can only continue until there are no more sticky places showing, though. When there's no exposed oil on the outside, the dirt goes farther into the element before it encounters oil and gets trapped. When the oil at that level is covered with dirt, the new dirt goes deeper still, until it eventually gets all the way through.

So, you have to oil them, and the oil has to be worked entirely through the foam element until the entire mass of foam is coated. I use Maxima FFT oil, but Bel Ray is also good, as is the oil supplied by Twin Air. The thing that distinguishes these is that they are extremely sticky/tacky and stay that way without drying out and loosing their ability to grab and hold dirt.

You will need a box of rubber mechanic's gloves (auto parts). There are two ways you can do this. One is to pour a bunch of the oil in a tub, dunk the filter and squeeze the excess out. I prefer to put a little squirt top on the bottle and apply the oil to the filter a bit at a time and work it through, adding more if I need to. Squeeze/knead the oil in, don't wring it, until the filter is thoroughly oiled, no missed spots (check along the edge of the filter base). Then hang the filter up over a trash can or whatever for 8 hours so any drip-off will happen there instead of in your air box. Never run a filter that hasn't been allowed to set up for at least four hours, or the sticky oil may be sucked into the carb.

Tip: Installing this sticky thing will be easier if you put the filter in a plastic grocery bag, slide into place, and then work the bag off it. The sub frame and air box won't get oily, and the filter won't pick up any dirt.:busted:

To clean them, I find it works best to set up a bucket specially for the purpose. Get one that has a lid you can snap in place to keep it closed. Put 3 gallons of mineral spirits (paint store) in it, and use it to rinse and squeeze the filters until the dirt is out. Hang them to dry for a few hours, then re-oil. You can use the same solvent for 6 months or so pretty easily, then take it to a auto parts store that takes used oil and dump it. I cannot emphasize enough how much happier you will be with mineral spirits or shop solvent than with things like gasoline or lacquer thinner. MS is less volatile, less flammable, less toxic, less harsh to your skin, and every bit as effective. Paint thinner is a good substitute in a pinch. Diesel is much more toxic than it seems, and is a lot oilier, as is kerosene.

What makes this a lot easier is to have at least two filters. You can oil one and get it ready, then remove yours, clean it, hang it, and put in the fresh one. You can also oil one in advance and bag it to have ready at a moment's notice, but be sure you let the filter hang out for a day before bagging, or the oil won't "set".

  • Wes Woodin

Posted January 29, 2008 - 08:59 AM

#4

Tip: Installing this sticky thing will be easier if you put the filter in a plastic grocery bag, slide into place, and then work the bag off it. The sub frame and air box won't get oily, and the filter won't pick up any dirt.:busted:

Never thought of that. Great idea.:worthy:

  • stroker101

Posted January 29, 2008 - 02:53 PM

#5

gr8 write up gray.

mineral spirits is what i use also to disolve the foam filter oil on the filter. but i also use "power clean" on the filter after rinsing the mineral spirits from the filter with water. the power clean will actually clean the dirt out of the foam filter, unlike the mineral spirits. using the back-flushing method to insure the dirt is rinsed out rather than further into the filter media. cheers

  • grayracer513

Posted January 29, 2008 - 03:07 PM

#6

That's a good extra step, but at the risk of sounding crazy, what's the difference if you don't get all the dirt out?

A good rinse with the solvent will remove nearly everything, leaving only the very fine dust that is suspended in the solvent as you rinse it. That dust will be held in the filter by the new oil, and so cannot cause any problems, as long as you oil it.

I won't go as far as to tell you that your way isn't better, because technically, it is. I just don't see it as being necessary.

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  • cj650

Posted January 29, 2008 - 03:09 PM

#7

Just a little gear oil and some greese to seal it off

  • smoove

Posted January 29, 2008 - 03:43 PM

#8

NoToil air filter products are the best they come with cleaner, grease sealant, and foam filter oil, all the things you need. if your shop dozent have any tell them to get some! or i bet they that they sell it here on thumpertalk.com i have a spare air filter(pre oiled) i keep with me at all times. i clean my air filter every other ride some times every ride. just good preventive maintenance:thumbsup:

  • grayracer513

Posted January 29, 2008 - 04:21 PM

#9

I tried No Toil, and was disappointed by its performance on two counts. It isn't tacky enough, and it doesn't stay tacky very long. As a result, I had fine dust bypassing the filter.

  • smoove

Posted January 29, 2008 - 07:23 PM

#10

I tried No Toil, and was disappointed by its performance on two counts. It isn't tacky enough, and it doesn't stay tacky very long. As a result, I had fine dust bypassing the filter.


i think your right...and thats why my carb has been more gritty then usual. i thought if i switched air filters brands it might help. but i havent ridden very much since to know yet. now i know what it is. thx greyracer for getting me straiten out on no toil.

  • CRFsean

Posted January 30, 2008 - 03:42 PM

#11

I tried No Toil, and was disappointed by its performance on two counts. It isn't tacky enough, and it doesn't stay tacky very long. As a result, I had fine dust bypassing the filter.


Ya, the UNI filter oil seems to work well

  • TJR

Posted January 30, 2008 - 04:12 PM

#12

I was Bel ray user for as long as I can remember. Tried the No-toil 2 years ago and have been very pleased with the product. I have a 06 YZ 125,YZ 250, and 07 YZ450f. I use the pro-flow NO-toil filters cleaner,oil and rim grease. I oil the filters from the inside out and work the oil into the foam until it is evenly coated inside and out. Then use the rim grease and install the filter in my bikes. I change filters every time i ride and check the inside of the air boot for dust etc. I have yet to get any dirt to pass through. I have rode in extreme dust this year as well. I did not trust this stuff at first but, I am sold on the system. It is easy to clean and use. I may use too much oil, but I want good coverage on my filters. I like the belray and others too. I just like being able to clean my filters in the sink. It also cleans the drain/food processor. Anyway, a good air filter is a clean one.





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