Do K&N Air Filters Work?

 Do K&N Air Filters Work?

I rarely do service tips or 'how to's'  but with so much dis-information out there about this specific product I feel the need to share my experiences. 

I've had a K&N air filter on this motorcycle since 2012 and we've ridden in a huge number of difficult conditions. This year I am re-shipping the bike to Europe for a couple more trips and wanted to do all the needed service work to ensure the bike is well maintained for the duration.

As you know the K&N air filters are a 'reusable' filter. I've used them for 20 some years in the Porsche we had, previous and current trucks, and our cars. The engineering concept is simple but technical. You can read about it from K&N directly.

This year I wanted to refresh my re-oiling technique and thought I'd check Youtube to see what was out there. Like everything else there are good and bad videos and information. One that struck me was a guy that claimed he did a deep technical analysis of the contamination of oil in a Ford truck and associated it to a K&N filter. Since I'm an evidence based guy, comparison analysis' needs to be done in a controlled environment. This test was anything but that. 

His conclusions were based on what he found in his oil, 

• based on using two different types and brands of oil 
• driving in an uncontrolled field environment without clarifying them
• (two different service intervals, one using a K&N filter and the other an after market single use paper filter that reputed to be of better quality, pleats and fabric, than your normal replaceable filter.  

That introduced too many variables to be linked to a single product, the K&N air filter or conversely a replaceable paper filter.

So I took the time to write this from a single service cycle experience with my K&N air filter and our motorcycle. So the service cycle was 8764 kms. When the air filter was removed the exposed side had bugs, fluff and a dark brown 'dust' colored appearance on the tops and down the sides of each exposed pleat. The unfiltered air side of the top housing on both the exterior and interior were dusty as you would expect.

Exterior of the Air box top showing dust

Interior of the air box top on the under side
 above the filter element

But when I lifted the filter out to do the service work this is exactly what I saw. The two fuel injection throats and secondary butterflies were perfectly clean as was the whole of the internal casing. No trace of dust existed inside.

Untouched when K&N filter removed
perfectly clean

So this example shows that no perceptible airborne particulate dust penetrated the filter element material. I'll let that be a testament to the performance of the product and the ease of correctly servicing the filter by an owner.