Oiled air filters in fuel injected bikes...?

Discussion in 'Technical & Maintenance' started by Bob, Nov 17, 2020.

  1. Bob

    Bob Active Member

    Anyone here use K&M BM-1204 washable oiled air filters on their fuel injected bikes?
    Last edited: Nov 18, 2020
  2. Trash

    Trash Well-Known Member

    I installed one on my BMW K1600GTL, and didn’t notice any appreciable difference in performance.
    Of course, K&N’s selling point is that you will never have to purchase another air filter, along with their claim of increased performance.

    I was considering doing the same for my current Triumph Trophy, and discussed the subject with my go to Triumph Master Mechanic at GO AZ Powersports in Scottsdale. He was quick to dissuade me, saying that the bikes he services with K&N filters have dirtier throttle bodies downstream of the filter, plus also require more frequent valve adjustments than the same bike with an OEM filter. Did my mechanic say that using a K&N filter would destroy the engine? Nope. He just said that it would contribute to accelerated wear.

    If you think about it, it makes perfect sense. There has to be a reason that K&N claims better airflow, and it’s because of less restrictive filter media. Consequently, more particulate gets through to the engine internals...
  3. RossKean

    RossKean Active Member

    It would be interesting to compare engine oil analysis between a standard filter and a K&N. The silicon, in particular, is indicative of "dirt" getting through and the iron and aluminum (and other metals) will show as wear.
    I have also heard the comment about oil deposits downstream. I have used K&N on carbed bikes but, to be honest, this is more a matter of saving a few bucks a year on NOT replacing the air filter rather than performance. Despite what they say, very few modern engines are starved for air during normal operation so a filter that flows more freely will make little or no difference in power output.
  4. Bob

    Bob Active Member

    Thanks Trash and RossKlein.
    I ordered the new air filter when I dropped the oil and oil filter last week. I thought I was ordering a paper one.
    There's no reason for me not use the BMW (M a h l e) OEM paper filters which is what's in it now, I'll just need to return the K&N and look elsewhere.
    I've used K&N oiled air filters on carbed dirt bikes in the past but think I'll just stick to the paper ones for the GS. Pic below for the size comparison, OEM on the left:

  5. skibum69

    skibum69 Well-Known Member

    I put a K&N air filter on a vehicle once and my mileage went down the tubes instantly. I've never used them again.
  6. fortech

    fortech Active Member

    I had a K&N on my 2006 CBR600 but it was 100% street machine. I did hear about them having less filtering capacity than a normal filter so never bothered on my later bikes.

    I had an oiled foam. UNI on my KLR, it worked well but carb.

    My Yamaha Grizzly has an oiled foam filter as well that seems to work well. More dirt than your typical ADV bike and the throttle bodies were clean when I serviced the filter a few months ago.
    Bob likes this.

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