K+N air filter time's up.

Discussion in 'Airheads' started by ME 109, Dec 6, 2017.

  1. mball

    mball Adventurer

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    One thing I didn't see mentioned in this discussion (apologies if I missed it) and didn't seem to be shown in the pictures, is that the K&N's won't filter well without applying their filter oil.
    #21
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  2. ME 109

    ME 109 Long timer

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    I did mention using their oil in the first post, but also assume most people will be told to use oil when they buy a K+N filter.
    #22
  3. bmwrench

    bmwrench Long timer

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    When you buy a new K&N, it comes pre-oiled.
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  4. ME 109

    ME 109 Long timer

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    There ya go. I can’t remember last week, let alone when I bought it. :D
    #24
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  5. bmwrench

    bmwrench Long timer

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    Ain't aging a bitch? When K&N started selling filters for the street, they were shipped dry, with a squeeze tube of oil in the package. That's how old I am.
    #25
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  6. shinyribs

    shinyribs doesn't care

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    I've seen several engines die from being fed dirty air through a K&N air filter. I have never seen an engine failure due to poor air filtration that was NOT connected to a K&N filter. I'm not talking about catastrophic explosions, just rings/cylinder walls extremely worn down prematurely.

    If you oil a K&N filter heavy enough to actually filter well....it can't breathe worth a damn.

    You cannot out-filter a paper filter, and paper filters flow much, much more air than most people like to admit.

    I used to drag race an old '48 Olds coupe that had a 1,000hp big block in it. For shits 'n' giggles, we once threw a stock air cleaner assembly off a 1972 Chevy truck on the motor with a standard Purolater air filter from Advance inside. I don't recall the exact numbers, but my 1/8 mile elapsed times dropped in the hundredths of a second. Trap speed mph variations was in the tenths of a mph. The variations were so small that you have to admit there was actually no difference at all.

    I'd run a paper filter in my dirtbike if they made them. Oiled filters are 1940's tech, plain and simple.
    #26
  7. misterpepper

    misterpepper Been here awhile

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    I'm up to close to 350k miles with a K&N filter between all my vehicles over the past 20-something years. It's one of the first additions I typically make. I have no idea if or how much extra power they make, but I'm not concerned at all about reliability. I drove one car over 200k miles with one in. I do like that I can clean the filter whenever I want, and that for the length of time I typically keep my cars they save me a lot of money. I did come across the following link recently and thought the results were interesting.

    https://jalopnik.com/how-sticking-a-salad-bowl-on-your-engine-can-make-more-1820402800
    #27
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  8. Wirespokes

    Wirespokes Beemerholics Anonymous

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    There are a lot of us here who don't believe that new fangled stuff is necessarily better. I tend to believe that oil bath air cleaners do an excellent job. And speaking of K&Ns wearing out an engine - there are way more testimonials of guys running hundreds of thousands of miles with them and no engine trouble.

    Jim - I have to correct you on your math - that wasn't 3% but a 2% difference.

    I do agree - it doesn't speak well of K&N that they never corrected the Airhead flat filter, but once modified they do work well.

    That second graph is pretty interesting. What it tells me is that once a paper filter gets clogged, air pressure forces it to flow, pushing the dirt through. With the K&N, you'll notice, as it gets restricted, if allows much less dirt through than most of the others. Normally filters filter best the older they are - but evidently, once they've gone too long, they can allow a large amount of unfiltered material through. Oil filters will collapse, but air filters will start passing all of that collected particulate right on through. Sounds like a good reason to use the K&N.

    Shinyribs - I'm curious how it was determined the K&N was the reason for the top end failure? Seems there could have been a number of other reasons, possibly unrelated to the mechanical side of things.
    #28
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  9. misterpepper

    misterpepper Been here awhile

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    When I see test results for K&N filters I often wonder how they account for the loss of filter oil that inevitably happens when you install a freshly oiled filter. And don't tell me filter oil doesn't gush like an oil rig off those things. How else would people be fouling their mass air flow sensors just by driving behind somebody running a K&N filter?
    #29
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  10. Jim Day

    Jim Day full manic mechanic

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    ....and paper filters are 1915 tech, but whose counting. :D
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  11. Jim Day

    Jim Day full manic mechanic

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    Dyslexia bites me in the ass again :lol3

    Have you heard the proverbial "Measure twice, cut once"? I measure four times :D
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  12. ME 109

    ME 109 Long timer

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    I wouldn't say I get worried, but I do get a bit anxious waiting for the next sports bike to come along.
    One's too many and a hundred's not enough. :evil
    #32
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  13. aptbldr

    aptbldr easy rider

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    "..what if one were to put a light spray of K+N oil on a paper filter? ..."

    Its film may bridge the paper filter openings, restricting air-flow.
    #33
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  14. bmwrench

    bmwrench Long timer

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    "...and it's still too short."
    #34
  15. TheProphet

    TheProphet Retired; Living the Dream

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    FYI, K&N warranty's both the filter, and the engine, if you were the original purchaser:

    https://www.knfilters.com/warranty.htm

    Like others here, I use K&N air filters on all my cars and bikes. It's the first thing I do when I purchase a new vehicle, and have never had a problem, and have achieved 200K+ miles on numerous cars, 80K and 71 K on bikes, and am extremely pleased with the performance. None have ever had air filtration related problems, and the engines were like brand new when finally sold.

    Could it possibly be operator error at times?:dunnoRead the warranty and the instructions for proper use, etc. Maybe it's the wrong application? That filter in post #1 looks dry as a bone, and shows a great amount of dirt, so it couldn't have been solvent cleaned prior to the photo. If you let the K&N run dry, then it probably hasn't been maintained properly, or at least not maintained (cleaned and oiled) on a timely basis.

    When you view a properly maintained K&N filter, as a result of the red colored K&N oil, it should appear at least slightly red/pink. It may be that K&N air filters are more for those that meticulously maintain their rides, as it takes some additional care, steps and attention Vs those that are less stringent about such things.

    See Here:
    #35
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  16. Uke

    Uke visualist

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    You should have used a lifeline . . . .

    99.93 - 96.8 = 3.13
    #36
  17. Jim Day

    Jim Day full manic mechanic

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    Followed by... "If you do it twice it better be nice!"

    That's actually my friends Al's favorite. When I build something it's almost always dimensionally correct, but I'm cheap, a perfectionist, and hate to have to redo projects.

    I also like: "Sometimes we measure with a micrometer, mark it with chalk and then cut it with a axe." :D
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  18. Jim Day

    Jim Day full manic mechanic

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    That math seemed simple enough to me, but I think he actually read the reports.
    #38
  19. Cletus Runswithscissorsguy

    Cletus Runswithscissorsguy hiding in plain sight

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    I've been using the round filter on a few airheads in the garage. Also use K&N branded pod filters on the Eldorado parked next to them, which came sans air filter box.. Never any problems, over 100K on a couple of the bikes. My R1100GS had a K&N on it for 160K. My Kawasaki Concours for over 100K but it failed to filter to the deer properly therefore it is no longer with us..
    I've always glanced and run a finger down the intake tract every so often and have never really found anything surprising.
    Usually the filter service interval for me is every few oil changes or so, and I can remember only doing it on a couple of my bikes MAYBE once or twice.
    I have however seen issues with using the K&N, accelerated ring wear, obvious signs of dirt in the intake, etc.
    Just about every time, it has been operator error. Cleaning the filter AT EVERY OIL CHANGE, installing a 'modified' filter to allow more air flow, "making" their own filter because "trying to find one for the Alfa Romeo GTV6 was too hard" or my favorite- "I didn't put oil on it because I didn't want oil in my engine"
    Like a hammer, if used correctly-the ACTUAL failure rate is slim to nil.

    Once again, I use Rotella 15w40 in just about everything, Michelin Pilot Activ's on most of the bikes, and 40/42 are my pressures. :lol3
    #39
  20. ME 109

    ME 109 Long timer

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    I do have the proper K+N cleaner and oil. I've found that if I use a little too much oil it gets into the airbox and makes a mess. I haven't drowned the filter in oil by any means but I've learned not to overdo it.
    Last oiling was within the last 10,000 k's. Longer than that for a clean, but I thought they were meant to accumulate x amount of crud in order to function properly.
    When I've washed the filter it's been with the K+N cleaner only, and run under a gentle flow of cold water.
    At this point it would be worth cleaning the filter again and assessing the state of the filter media for even distribution.
    Maybe this filter is not ideal for high rpm work and is actually restricting the airflow and causing a rich fuel mix? The engine doesn't seem to suffer from power loss, but that may not mean the mixture isn't rich.
    My bike has consistently used more fuel than my brother's same year RS.
    Maybe if there is restriction to airflow, it may pull more from the crank ventilation system?
    I can see I'm about to embark on a crusade to sort this out, and with a new paper filter I'm going to do some comparisons and see what the evidence is.

    It's Friday morning, and two weeks since I ordered my carb parts from Motobins. Hopefully they get here today so I can work on it tonight and over the weekend.
    #40