What are air filters used for? And how do they work?
Just like human beings, motorcycle engines need clean air to run efficiently. The air filter therefore plays a vital role in filtering dust, dirt and debris as air is drawn into the engine. Without it, the contaminants would lead to incomplete combustion, increased fuel consumption and a smoky exhaust system. The pollutants would wear down key components such as engine pistons and cylinder walls, leading to costly engine repairs.
The filtration component itself is made of a porous material, allowing air to pass easily and collecting large to fine particles. Filters are available in a variety of materials and designs, varying in performance and durability. Over time, the air filter reaches its full capacity and becomes clogged with dirt. This will restrict airflow into the engine. Just replacing it or cleaning a reusable one can make a significant difference in your bike’s fuel economy. Check out the types of replacement filters available below.
Common Types of Motorcycle Air Filters
These products are the cheapest in the market because they are easy and inexpensive to produce. The paper filter element looks a bit like the filter paper you use in your coffee machine. The material is pleated to increase its filtering surface and provides reliable filtering at low cost. The main disadvantage of these products is that they get dirty very quickly and are not reusable. They are not suitable for off-road vehicles.
These filters are particularly popular due to their durability and high performance qualities. They are made from a cotton gauze material which is coated with oil. The fabric is highly porous which increases airflow, while the oil traps any dirt or dust that tries to pass through. They are lightweight and easy to clean and oil. The downside is that they are more expensive than your typical paper filter, and sometimes oil can mess up the airflow sensor. However, the increased throughput capacity and long life make it worth it.
K&N’s SU-5589 Long Life Filter is a classic example of a popular cotton gauze product, designed to increase engine horsepower and torque. It is made of several layers of woven cotton gauze for better filtration. The product is well known for its long lasting properties and the brand offers a “million mile limited warranty”.
Oiled foam filters are a cheaper reusable alternative to cotton gauze filters. Their main advantage is that they do not interfere with air circulation filters. The principles of operation are similar, except these products are thicker and still work when wet because the material and oil are not absorbent. However, they clog very easily and may need to be washed and oiled after each ride.
When to replace your air filter
If your filter is paper, manufacturers generally recommend replacing it at least once every 20,000 km. Foam components can typically travel 1,500 to 2,500 miles before cleaning if used in a relatively dirt-free environment. The cleaning interval for cotton gauze components is much longer. Consult your vehicle manual for more information on maintenance intervals.
Important: Always check that the replacement product is compatible with your motorcycle before purchasing a new air filter. The website or catalog should include a list of suitable applications. For example, K&N SU-5589 is ideal for Suzuki motorcycles, such as Suzuki GS motorcycles (1989 – 2008, 27 – 48 PS, petrol) and VZ motorcycles (1997 – 2006, 50 – 53 PS, petrol) .