&N is a legendary name in the motorcycle performance field. We all know the story of Ken Johnson and Norm McDonald (K for Ken and N for Norm) and their idea to build better air filters by simply wanting to make it bigger (for greater surface area and filtration). But how to increase the size of the filter and still fit it into the confines of a motorcycle’s intake area? Their solution? Pleat the filter element. Thus the K&N filter was born several decades ago. Since that time K&N has refined, redesigned, evolved and revolutionized the field of filters and is easily considered the company at the top of the game.
     K&N was on the cutting edge back in the day and remains there today via an incredible amount of air filtration testing and scientific research that goes on in the K&N facilities as well as in independent laboratories. As the leader and originator of the high-flow performance air filter, K&N is always looking for new ways to provide excellent protection and maximum power for your motorcycle, and just about anything else with an engine. In 2006 more than 1,600 vehicles were tested by K&N’s R&D group on dynamometers in the U.S., United Kingdom, and the Netherlands. In addition to these power and torque tests, they also performed more than 200 filtration tests and more than 1,200 air flow tests with their in-house state-of-the-art test equipment.



n addition to being widely recognized as the superior air filter system for most motorcycles, K&N air filters feature High-Flow Technology to help motorcycles breathe easier, giving riders the power they crave without the reliability headache or bolt-on problems often associated with high performance, aftermarket parts. In other words, in addition to being a better air filter then stock, a K&N filter also enhances the performance of the motorcycle via high-flow technology.
      Here is just one selling point to your K&N customers. At its most basic level, an engine is an air pump. Just think about how an engine works, air is sucked into the carburetor where it is mixed with fuel. This fuel/air mixture is then pulled into the combustion chamber where it is compressed and then ignited to create an explosion, which moves the piston creating power. That explosion is the basis for internal combustion. The explosion is the result of the air/fuel mix. Therefore we can surmise that more airflow equals more air, more air equals more oxygen, more oxygen creates a more powerful, cleaner explosion, and a more powerful explosion equals more power. Therefore, more air entering the engine increases the efficiency of the combustion process creating more horsepower and torque. Horsepower is a measure of the engine’s maximum power while torque measures how quickly you can accelerate. Both added horsepower and torque are extremely important to anyone wanting added performance out of their motorcycle.
     The K&N Filter is designed to increase engine performance in both horsepower and throttle response by reducing airflow restriction. This works in several ways; first because the K&N Filter is pleated the size of the filter itself is typically larger then conventional filters, giving the K&N filter a much larger surface area for air to enter (think of an accordion or bellows fully expanded). Next, maintaining optimal, unrestricted airflow becomes a problem when it must pass through a filtering medium. The level of air resistance varies depending on the size, surface area and physical attributes of the filtering medium. The K&N filtering medium is a pleated, multi-layered oil impregnated surgical cotton fabric which traps dirt with a combination of the oil barrier and the “maze” effect of the pleating of the filter element. The bonded cotton/wire mesh then straightens the airflow reducing the turbulence and allowing straightened and filtered high volume air to enter the intake system.
     Therefore, because a K&N Filter is pleated it is actually larger then most conventional foam filters and offers a greater filtering surface which can trap more dirt without clogging and can pass a larger volume of air to the intake system. The result is greater airflow and increased performance.
     This is a great product for consumers who can’t afford many of the high-end performance products for their bike. Performance gains by simply installing a K&N filter are noticeable and relatively inexpensive. Plus they have the added benefit of helping the engine last longer.
     A dealer can be confident that K&N will back its product and fulfill their requests. There is a printed and stand behind Million Mile Limited Warranty® for on-road filters and a 1-Year Limited Warranty® for off-road and racing filters. Plus, K&N is still 100% made in America! Every tool and mold is built in-house and every air filter is made in the USA, laboratory and field-tested and ISO certified. Parts Unlimited is your source for K&N motorcycle filters, cleaning kits, and rechargers.



n air filter element becomes an insurance policy when used in off-road applications. Competitors will sacrifice a high-tech engine for a chance to win a race, but to win, they must finish. If the engine ingests too much dirt and debris, it may die an ugly death before the vehicle can cross the finish line.
     You might think this would be the perfect application for an inexpensive, replacement foam filter. But remember, in competition a little extra horsepower can mean the difference between coming in first, or finishing second. The air filter now becomes an important part of the performance package. Many WORCS, GNCC and Desert races have been lost due to clogged filters.
     K&N air filters are designed to provide minimum restriction long after disposable air filters have begun choking an engine. In other words, due to its characteristics, the restriction of a K&N replacement filter increases at a slower rate when compared to a disposable filter, i.e. a K&N filter will last longer under the same conditions. That’s why many off-road competitors choose K&N filters.
     In a hypothetical 24-hour off-road race to further the point, a properly prepared K&N filter will see the racer through to the end with room to spare. The equivalent disposable air filter, on the other hand, will need to be replaced with a fresh element to ensure the engine has an adequate supply of air to complete the course. A K&N will provide excellent filtration without sacrificing airflow for a longer period of time–that’s performance with value.



&N designs its air filters to provide superior filtration of the contaminants that can harm your engine while maximizing the airflow characteristics of the filter in question. The ability of an air filter to protect your engine is generally measured in accordance with testing procedure ISO 5011. They subject a sample of K&N filter designs to this test procedure using Coarse Test Dust, which includes particles ranging in size from less than 5.5 microns to 176 microns. As a point of reference, a human hair is approximately 50 microns in diameter. The result of the above test procedure is a specific air filtration efficiency number. This efficiency number represents the percentage of test dust retained by the filter and thereby kept out of an engine. K&N’s stated goal is to design air filters to achieve maximum airflow while targeting overall filtration efficiency at 98%!
     Both airflow and dirt retention are critical to engine performance. For this reason a consumer should always evaluate an air filter based on both its filtration efficiency and airflow capabilities. It is very easy to design an air filter that exhibits high airflow simply by reducing its filtration to unacceptable levels. K&N filters and designed and tested to deliver both high airflow and great filtration.