With a bit of simple maintenance a quality air filter could last the lifetime of your motorcycle. Here we look at the different types, what it does and of course, how to maintain and clean a motorcycle air filter.
Why your motorcycle needs clean air filters
The best way to think about an air filter is to see it as your motorcycle’s lungs.
Our motorcycle’s need to be able to breathe properly just like us humans, when they can’t it has a knock on effect on their performance and can be overall detrimental to their health.
An air filter on a motorcycle simply prevents small particles of road debris, dust and dirt from getting into your engine; keeping air flowing into your engine without the risk of contaminants.
It sits somewhere between your air intake and engine, usually inside an air box.
A dirty or clogged air filter can lead to poor fuel economy and a loss of power among other issues down the line with unwanted particles getting into your engine damaging the finely crafted internals.
Eventually the air filter will get clogged up with debris and need to be cleaned or replaced in order to remain effective.
So, you see, the small, humble and often overlooked air filter on your motorcycle is actually one of the most important components key to your engine’s health, which is why it is important to look after it.
Different types of motorcycle air filter
There are considered to be three main types of air filter: paper, gauze, foam.
Paper Air Filter
Most road bikes come with a paper filter as standard. The paper is thick and porous similar to the paper filters in coffee machines.
The paper tends to be pleated which increases the overall surface area which serves the sole purpose of increasing the amount of air that can be pulled through into the combustion chamber.
A paper air filter is very effective at blocking particles and that is why many manufacturers use them as standard.
However, they generally need to be replaced when they are no longer effective as when you clean them (however, carefully) you run the risk of puncturing the paper rendering it useless to combat debris.
Gauze Air Filter
A gauze filter replaces the paper element with layers of fabric, quite often cotton. These are separated by wire mesh frames.
The gauze is soaked in oil which is what catches any particles and the fabric is more porous than paper allowing for increased airflow.
These are often retro-fitted on motorcycles that have been modified or remapped in an attempt to unleash more peak power and torque or when an air box delete modification is carried out such as in the photo above.
Gauze air filters can be washed, re-oiled and reused.
Foam Air Filter
These are much thicker than the other two with larger porous holes visible to the eye.
They allow maximum airflow but as the surface is also covered in oil particles are efficiently removed and blocked from carrying on into the engine.
This type is most common on off-road bikes. They can operate effectively in dusty areas where the foam blocks contaminants and the large holes keep the air flowing.
Paper filters in off-road environments get blocked up very quickly and need replacing with minimal use in comparison.
Foam filters like gauze can be removed, washed, re-oiled and reused.
Can all motorcycle air filters be cleaned?
All motorcycle air filters can be cleaned but it is far easier to change a paper filter than it is to attempt to clean it.
Paper filters are cheap to replace so this is by far the better option.
Foam and oil filters are easy to remove, clean and reuse with minimal fuss and will withstand many cycles of this before finally needing to be replaced.
In fact many fabric and foam air filters will last the lifetime of the bike itself if you look after it properly, the exception here being dirt bikes as theirs is subjected to a lot more abuse than others.
How to clean motorcycle air filter
Paper
Paper air filters cannot be rinsed in water as it will disintegrate the paper. You can simply brush them off carefully, loosening any particles and this will extend the filter’s life slightly.
Smaller particles however will not be removed using this method and so the filter will continue to build up until eventually replacement is necessary.
Gauze
The best way to clean your gauze filter is to use a specific cleaner which will not only remove any particles but the oil it has been soaked in too.
K&N are one of the most well known brands of gauze type air filters and they sell their own air filter cleaner set for cleaning and re-oiling your filter.
Essentially you spray your filter vigorously with their cleaner ensuring you are thorough inside and out of the filter.
You will then usually rinse in clean water until you are satisfied all particles and old oil has been removed.
If you don’t want to purchase an air filter cleaner kit you can use soapy water to give it a good cleaning before rinsing but remember, you will still need new filter oil to spray on once it’s cleaned and dried.
Once thoroughly cleaned you need to wait for the filter to completely dry before applying the fresh air filter oil. Don’t try and hurry this by using a hair dryer or other heat source as it can break down the glues used to hold the gauze filter together.
For a fabric filter this is an easy job, just thoroughly spray with oil ensuring complete coverage of the fabric held on the wire mesh.
Then you are good to go, replace your air filter on your bike and get riding.
K&N Air Filter Cleaning Kit
Developed for and by K&N air filters but works on all gauze type filters.
Includes the K&N specially developed Power Kleen, a degreaser that dissolves the old oil on your filter allowing it to be rinsed away with clean water.
Also includes K&N red filter oil which provides exceptional contaminant capture.
Restores air flow efficiency so your K&N air filter performs like new
Foam
Cleaning your foam air filter is the same as above although it is best to remove the foam from the casing altogether where possible so you are just dealing with the foam itself (like a sponge).
You can then be sure to remove all the gunk before rinsing in water until clean.
Again, either use a specialized foam filter cleaning kit or soapy warm water.
Includes both air filter cleaner and replacement oil.
Simply spray liberally with the cleaner and then thoroughly rinse in clean, warm water. Allow to completely dry and then liberally spray with the new oil.
Cleaning a dirt bike air filter
As already mentioned many off-road bikes will use foam type air filters as they are more suited to the more hardcore conditions of dirt and dust.
Maintaining an air filter on your dirt bike is no different to a road bike, the only difference is you will find yourself cleaning your filter far more often.
Many off-road riders find themselves cleaning their air filter after every off-road session to maintain peak engine performance.