K & N Motorcycle Air Filters What are the Benefits

This is an overlook of some common questions regarding K & N Air filters for your Motorcycle.

K & N Motorcycle Intake

1.How will a K&N filter affect my vehicle’s fuel economy?

There is a relationship between air filter restriction and mileage. The theory behind this is simple, the harder an engine has to work to suck air through the intake tubes and air filter, the more gas gets wasted in the process. Replacing a dirty or clogged air filter is one of many recommendations the U.S. Department of Transportation suggests for improving fuel economy (see http://www.fueleconomy.gov/feg/FEG2007.pdf).  Many K&N users report an increase in their fuel economy after beginning to use our air filters, as noted on our testimonial page. However, these experiences do not mean you will also experience a change in your mileage. We certainly understand why it is theoretically possible for a consumer to experience a mileage increase after installing a K&N air filter or intake system, however, we do not go so far as to make a general claim that our air filters and intake systems will provide an increase in mileage.

It is virtually impossible to make sweeping and general claims about mileage. Even the EPA fuel rating numbers for new cars are often not representative of the mileage you actually experience. There are many variables that affect mileage such as: tire inflation, the type of fuel, weather, elevation, the speed at which you drive, the gear in which you drive, the speed with which you accelerate, engine maintenance, excessive idling, cruise control, the grade of motor oil you use, and of course, the condition of your air filter.  In short, mileage is complicated.

K&N filters are less restrictive than disposable paper or synthetic air filters and K&N Intake Systems are less restrictive than the factory installed air path. So K&N filter technology could be an important tool, when combined with other elements, to help keep mileage as high as possible.

Oh yeah, there’s one more limitation imposed by science. If you take advantage of added power by driving more aggressively, you will reduce mileage. You cannot have your cake and eat it too.
2. What increase in horsepower should I expect from a K&N replacement filter?

K&N direct replacement filters which install into your vehicle’s factory air box can provide an increase of between 1 and 4 horsepower.  Results will vary depending on your vehicle, driving habits, load on the engine (towing for example), existing air system restriction, and other factors.
3. What increase in horsepower should I expect from a K&N air intake system?

K&N makes several different types and configurations of performance air intake systems.  Depending on the year, make, and model of your vehicle, only one style of intake system may be available for that vehicle.  All of our intake systems are dyno-tested and guaranteed to increase your vehicle’s horsepower.  Instead of making a general claim, we publish actual intake system horsepower increases for many part numbers and vehicles. To see the power gains of specific air intakes for specific vehicles, enter the part number in our part search or look up a specific vehicle in our application search.
4. How often do I need to clean my K&N air filter?

If you have not experienced a decrease in mileage or engine performance, chances are your filter is fine and does not yet need cleaning.  To be more specific, the filter does not require cleaning if you can still see the wire screen on the entire air filter regardless of how dirty it may appear. When the screen is no longer visible some place on the filter, it is time to clean it. When used in normal paved road, street or highway conditions, our replacement air filters that fit in the factory air box should require cleaning every 50,000 miles and our large conical filters on an intake system should require cleaning every 100,000 miles. When used in dusty or off-road environments, our filters will require cleaning more often. We recommend that you visually inspect your filter once every 25,000 miles to determine if the screen is still visible.

5. Can a K&N filter give my engine too much air flow?

No. An engine can only draw in a certain volume of air depending on the engine’s size (measured by such things as bore, stroke and number of cylinders).  Vehicles are designed to accommodate large changes in air pressure so they can operate at sea level or at an altitude of 14,000 feet.  Engine computers adjust the amount of fuel required as a result of changes in air pressure (density).  Air filter restriction when the filter is new and especially as the filter loads with dust will result in lower air pressure and availability similar to being at a high elevation.  High-flow air filters that were invented by K&N were designed to reduce the work necessary to pull air through the filter and to increase air pressure.  Increased air pressure is one of the key elements in producing more power.
6. Will using a K&N direct replacement filter void my factory warranty?

It is against federal law in the United States for a manufacturer to require the use of a specific brand of air or oil filter unless it provides a replacement air or oil filter, free of charge, under the terms of the vehicle warranty. For a more thorough discussion of this law known as the Magnuson-Moss Warranty Act, see our Vehicle Warranty Section of our Air Filter Facts page, and our Letter Regarding Vehicle Warranty and K&N Replacement Filters.

7. More airflow means you are letting more dirt through, right?

No.  Filtration testing measures the percentage of dust retained before the filter reaches a terminal test pressure, often 10″ of restriction above initial restriction. We use airflow as a simplified term to explain a more complicated physical process. The more precise description is restriction: K&N air filters create less restriction which helps an engine run better. An engine will only use the air it needs and our air filters do not result in an engine using more air than necessary. Rather, they result in the engine experiencing less restriction. The terms airflow and restriction are inversely related. Our air filters provide either less restriction at a fixed airflow rate; or more airflow as a fixed level of restriction. In neither case is more air being used than necessary.