What happens when you wipe the front of the throttle body, just in front of the butterfly? When I wiped off a decent layer of dust, that was the end of using K&N for me. YMMV.
K&N air filter after 2.5 years pic.
- Thread starter hardcore302
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What happens when you wipe the front of the throttle body, just in front of the butterfly? When I wiped off a decent layer of dust, that was the end of using K&N for me. YMMV.
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That filter is not even ready to be cleaned. Hit with a quick shot of fresh oil and run it. You should see the ones out of the dirt bikes. 1/4” thick dirt and cleaning them yields no power or performance gain. K&N oil is vegatable oil and can dry some over time. Afe oil is synthetic and does not dry out as fast.
K&N filters are for fools. They breath well but are terrible at filtering. A paper filter will do everything a K&N will except at full throttle, but paper will filter far better.
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As I type, it's 2025. I fell "prey" to the K&N filter and cleaning kit, because the forum said I would get 2-5 HP more. In retrospect, by 2001, 3 years after I got it, I realized if anything, my mpgs went down as the filter got dirtier. And they claimed it filtered better as it got dirtier. I highly doubt I ever got 2-5 HP more, and when I went back to OE paper filters, my mpgs went up.
Some guy had access to a mil dollar (a lot in the early 2000s) bench test equipment and showed how poorly their products filter and how badly it adversely affects airflow. K&N couldn't even afford the equipment to refute the claim. And yet, in 2025, they still are peddling the same products. How do they sleep at night (probably on a mattress with golden springs)?
really?
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Yes and it’s still good. I should have added that I live in the dry hot AZ dezert and that exasperates biodegrading and drying of the K&N vegetable oil. AFE is more expensive, seems thinner but is synthetic. K&N seems more sticky and when it gets dry a quick coat freshens it up just fine. I let them all get filthy dirty because opening up your clean underside risks tiny bits inside your motor. I think it was Johnny Weisman a major Kawasaki mechanic and world class suspension expert told me that the 250 and 450 bikes need rebuild because the owners pull their air filters to clean them too often. I know we are careful but those tiny bits that get in the intake and airbox when you pull a dirty filter off eats engines.
I accidentally let my paper filter go almost 2 years last time, so about 40k miles and it was not quite that dirty looking but close. I won't use a k&n because I work construction and it's like driving around and idling in a big dust cloud half the time. I also water the air box and wipe it off before removing the old filter because it's so dirty under the hood.
I've been using my paper filters at least 70k miles per
Is there a reason it has a weird wavy area that's clean?
Most likely based on the air box design and how it channels air through the filter.
OVERKILL
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I think I know the test you are talking about, was it this one?
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