K&N Air Filter Service

[t-man403]

How often do you replace or clean your air filter?
It has been 3 riding seasons for me so I did mine today.

Pre-filter.



Main filter held to the sun.



When I first got the bike I cleaned the filter as well and at that time it was probably cleaner than this!
Yes, cleaning it this time, there was a bit of dust in the pre-filter but nothing that needed me to service it at this time. There was no more dust in it than there was on the bike frame.
I find it strange that it isn't dirtier.  
Hate taking the tank off for no reason.

[Roidfingers]

Glad you brought this up. Look at your prefilter. You see all the dirt and dust etc... All accumulated at the front end of prefilter. It also happens with the oem filter too. If you look at the underside of the airbox, you will understand why. Seems to me, that all the air coming in hits the front of the filter due to the metal / plastic plate that forces the air that way.

I wonder if anyone has removed it? Seems you would get more direct flow with the bigger opening. Wonder if doing so would have a pos or neg effect?

[t-man403]

I wonder if anyone has removed it? Seems you would get more direct flow with the bigger opening. Wonder if doing so would have a pos or neg effect?

I looked at that plate and wonder the same thing. The plate could be removed and you would have a bigger opening on the inside but the inlet stays the same. I also thing that easier air in might mean re-jetting.

[h13man]

Hmmm, mine didn't come with a prefilter from the previous owner.

[sandy]

K&N says clean every 50,000 miles. My pre filter rotted away so I no longer have it with no change in the way it runs.

[t-man403]

K&N says clean every 50,000 miles.

 So that's the last time I clean my filter!!! 

[t-man403]

Hmmm, mine didn't come with a prefilter from the previous owner.

Might be there as it will stick in the cover.

[98valk]

A K&N lets your engine eat dirt.

After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms. Compared to the AC, the K&N  “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt

http://www.billswebspace.com/AirFilterTest.htm


This report presents the results of an ISO 5011 test of several air filters designed for the GM Duramax Diesel. The test was independently performed under controlled conditions using a $285,000 machine at Testand Corp of Rhode Island (manufacturer of the machine). Arlen Spicer, a GM Duramax Diesel owner/enthusiast organized the test. Ken an employee of Testand offered to perform the tests at no charge. (These tests typically cost approx $1700.00 per filter).  Ken, also a Diesel enthusiast and owner of a Ford Power Stroke Diesel, shared Arlen’s interest in performing an accurate unbiased test of different types and brands of diesel engine air filters. The filters used in the test were purchased retail and donated by Arlen and other individual Duramax Diesel owners. The detailed reports from the test have been compiled and are presented in the following pages. The final pages of this report present the behind the test.

 

ISO 5011 Test:

The ISO 5011 Standard (formerly SAE J726) defines a precise filter test using precision measurements under controlled conditions. Temperature & humidity of the test dust and air used in the test are strictly monitored and controlled. As Arlen learned in attempting his own tests, there are many variables that can adversely affect filter test results.  A small temperature change or a small change in humidity can cause the mass of a paper filter to change by several grams. To obtain an accurate measure of filter efficiency, it’s critical to know the EXACT amount of test dust being fed into the filter during the test. By following the ISO 5011 standard, a filter tested in Germany can be compared directly compared to another filter tested 5 years later in Rhode Island. The ISO 5011 filter test data for each filter is contained in two test reports; Capacity-Efficiency and Flow Restriction.

[..]

I used a K&N on my ST1300 for 130,000 miles.

I used a K&N filter on my previous Valkyrie for 60,000 miles.

Once it's time for a new filter on the current Valkyrie I will be using a K&N filter.

You pays yer money and makes a choice.

I cleaned mine every 25,000 miles because I tend to do a bit of forest road riding and the filter gets dirty.

[98valk]

I used a K&N on my ST1300 for 130,000 miles.

I used a K&N filter on my previous Valkyrie for 60,000 miles.

Once it's time for a new filter on the current Valkyrie I will be using a K&N filter.

You pays yer money and makes a choice.

I cleaned mine every 25,000 miles because I tend to do a bit of forest road riding and the filter gets dirty.

the spicer test is the industry test the same one K&N quotes, brags about the end of the test which shows the efficiency of their filter, but leaves out ALL of the dirt it let in before the end of test when it is highly inefficient and at the end of the test where it almost fully clogged and about to fail all air flow.
the cleaner it is the more dirt it lets thru. that's why they tell u clean every 50k miles the dirt it picks up is part of the filtration design.  it was designed for race track and off road racing.
it lets dirt in that wears the rings and cylinders, resulting in loss compression and loss of power and mpg. but the loss is over time and most do not notice it.
there are many tests out there that prove all of this esp used oil analysis that always shows high levels of dirt in the oil when a K&N is used.
and the filter for most applications provides zero HP gains and a lot see a loss, again this has been dyno proven.
The OEM filter is a high flow unit stops dirt and does last longer than 12k miles. mine is at 24k miles looks terrible but still no loss in HP or mpg.
Enjoy.

[..]

I used a K&N on my ST1300 for 130,000 miles.

I used a K&N filter on my previous Valkyrie for 60,000 miles.

Once it's time for a new filter on the current Valkyrie I will be using a K&N filter.

You pays yer money and makes a choice.

I cleaned mine every 25,000 miles because I tend to do a bit of forest road riding and the filter gets dirty.

the spicer test is the industry test the same one K&N quotes, brags about the end of the test which shows the efficiency of their filter, but leaves out ALL of the dirt it let in before the end of test when it is highly inefficient and at the end of the test where it almost fully clogged and about to fail all air flow.
the cleaner it is the more dirt it lets thru. that's why they tell u clean every 50k miles the dirt it picks up is part of the filtration design.  it was designed for race track and off road racing.
it lets dirt in that wears the rings and cylinders, resulting in loss compression and loss of power and mpg. but the loss is over time and most do not notice it.
there are many tests out there that prove all of this esp used oil analysis that always shows high levels of dirt in the oil when a K&N is used.
and the filter for most applications provides zero HP gains and a lot see a loss, again this has been dyno proven.
The OEM filter is a high flow unit stops dirt and does last longer than 12k miles. mine is at 24k miles looks terrible but still no loss in HP or mpg.
Enjoy.

ST did a consistent 42 mpg over its life.

[98valk]

[/quote]

ST did a consistent 42 mpg over its life.
[/quote]

understand.

Proven scientific used oil analysis, always shows excessive engine wear via high metal content when a K&N and other cotton/gauze filter types are used.
maybe the bike could have been doing better?, as it should have from being new to were the engine is broken in.

[t-man403]

I have used K&N over the last twenty years or there about.

Had one in the Expedition, F150 and the Valk. Funny thing is, I never purchased any of them as they were already there and I didn't know it till after I bought each vehicle. So all I have done is purchased the K&N kit for servicing the filters.

I took a look at the info posted by "98 Valk" and noticed K&N didn't fare to well. I'm not that technical as to all the science behind a product but in my estimation, I really don't think any filter manufacturer is going to produce a product that would deliberately ruin you engine. Whatever passed through the air filter would be picked up by the oil filter to a degree and if the oil analysis is showing dirt, then perhaps a better oil filter is in order ....... I don't know so correct me if you will.

What I do know, is I sold the Expedition to a friend with around 150,000 miles on it and it didn't use a drop of oil.
My F150 now has 178,000 miles on her and uses no oils as well.
The Valk, I do two riding seasons on an oil change and when I dump it, I always wonder why as it looks like it would easily go a third season.

I use Ams-oil with Wix filters. Having said that, I believe that if you follow the manufactures instructions be it an oil or air filter, it will give you the protection they say it will. 

[98valk]

I have used K&N over the last twenty years or there about.

Had one in the Expedition, F150 and the Valk. Funny thing is, I never purchased any of them as they were already there and I didn't know it till after I bought each vehicle. So all I have done is purchased the K&N kit for servicing the filters.

I took a look at the info posted by "98 Valk" and noticed K&N didn't fare to well. I'm not that technical as to all the science behind a product but in my estimation, I really don't think any filter manufacturer is going to produce a product that would deliberately ruin you engine. Whatever passed through the air filter would be picked up by the oil filter to a degree and if the oil analysis is showing dirt, then perhaps a better oil filter is in order ....... I don't know so correct me if you will.

What I do know, is I sold the Expedition to a friend with around 150,000 miles on it and it didn't use a drop of oil.
My F150 now has 178,000 miles on her and uses no oils as well.
The Valk, I do two riding seasons on an oil change and when I dump it, I always wonder why as it looks like it would easily go a third season.

I use Ams-oil with Wix filters. Having said that, I believe that if you follow the manufactures instructions be it an oil or air filter, it will give you the protection they say it will.  

how would the dirt get into the oil? it has to go pass the piston rings and cylinder wall, then when in the oil that oil is flowing through the tight clearances of the camshaft and main journal bearings. major wear. only a dual filtration oil filter system that can filter down to 1 micron would work. the best single filters only go down to 12-15 microns. it will get closer to 10 microns the longer the filter is used and why every other oil change of the filter is sometimes a good idea, there actually is a SAE test paper that proves this.  its been proven that most engine wear is caused by wear particles in the 5-10 micron range.
plenty of info at www.bobistheoilguy.com if interested as well as many other sites. some I have posted over the yrs, including my UOAs.
with how most are about their bikes, esp changing modern oil way to soon I'm maze how those same used an air filter which has been proven in testing to let in a ton of dirt and provides zero performance increase during normal riding operation.

remember K&N found a car yrs ago that had an undersized air cleaner as designed by the OEM. they put their airfilter in an saw an HP gain and that was their marketing ploy. taking the airfilter out would have seen the same gains. a correctly sized air cleaner would had shown zero difference vs a k&n. and now paper air filters are much superior than a decade ago, most as are all honda filters are now a synthetic fiber blend as are oil filters.

[BobB]

I service the K&N air filter every winter, but my gas tank is removed every winter, so it's easy to do so.  I am no longer using the foam pre-filter.  

Do not modify the air box.  Honda did it right.  There has been much discussion of air box mods here on this board.  Search is your friend...

[Fazer]

I did a desmog last fall and since I had the air box out anyway, I installed a new OEM filter.  Without realizing, I discarded the K&N filter which I thought was a dirty OEM--DOH!  Now I have the standard paper job, and will probably stay with it.  I don't ride in dusty areas much and at 4-5000 miles a year can do with the OEM.