5 Motorcycle Air Filter FAQ’s

From cleaning to replacing them, we’ve produced quite a bit of blog and video content related to air filters, particularly the kind that protect the airflow in motorcycles. 

As content creators, we often turn to the most searched questions on the web for inspiration. So rather than do another post solely about cleaning and/or replacing air filters, we did some research on what are some of the Web’s most searched questions regarding air filters for motorcycles. Here are our answers to 5 frequently asked questions about motorcycle air filters. 

Why are motorcycle air filters so expensive?

This one has no straightforward answer. For starters, we don't like the word "expensive." That's because we sell parts here at lower prices than our competitors (hence “The Alternative to Retail Prices” slogan) and we have a price match guarantee. Plus, what’s considered expensive is mostly subjective. The simple answer is that motorcycle air filters vary in quality, so there are cheaper and pricier air filters out there. Air filters are crucial to your motorcycle's health, and their quality and performance naturally affects the price. 

An air filter’s cost is affected by factors such as what material they’re made of (paper, foam, fabric, etc.), and whether they’re reusable or disposable. A better way to answer this question is to move on to the next question: 

Are expensive air filters worth it?

For this question, we’ll use K&N air filters as an example, since they’re a quality aftermarket brand we’ve featured prominently in our content. Yes, we believe high quality air filters like the ones K&N manufactures that could be considered “expensive” are worth it, or else why would we feature them in our blog content and videos? 

When you consider the level of quality high-flow air filters like the ones made by K&N provide, they’re not that expensive at all. These air filters are long-lasting, reusable, and allow more airflow into the engine. They’re also oiled to trap contaminants like dirt and bugs while allowing more air to pass through. In short, pricier air filters like the ones made by K&N are ultimately worth it because they save you money in the long run. They can be cleaned, oiled and reused, and last much longer than cheap, disposable air filters. We do have to note that while a high quality air filter may give horsepower a tiny boost, that really depends more on whether the filter is clean or dirty, as we found out during our Honda CBR600 air filter horsepower dyno test. 

What happens to an engine if an air filter gets wet?

Air filters can get wet for a number of reasons, including riding in rain, snow and mud. When a motorcycle’s air filter gets damp, the engine doesn’t perform as well as it should. That’s because water can restrict the filtered airflow that’s meant to pass through the engine. 

So is it bad to run a motorcycle engine with a wet air filter? It depends on how wet it is. If you ride your motorcycle regularly, a little water in the air filter probably won’t do any significant damage. That’s because the heat created by the engine plus the oxygen that passes through it should be more than enough to get rid of a little wetness in the air filter. However, a completely soaked air filter can significantly affect engine performance, including misfires, rough idling and starting problems. A soaked air filter essentially has the same negative effects as a dirty or clogged air filter. Keep that in mind when washing a reusable air filter, as letting it dry overnight is highly recommended before reinstalling it. 

What happens if there’s no air filter in the engine?

Can a motorcycle run without an air filter? Sure. But just because it can doesn’t mean it should. As already mentioned, air filters, well … filter out contaminants from the air intake of an engine. The motorcycle will probably run a bit without an air filter, but the damage could be catastrophic. Everything from the carburetor to the cylinder walls and pistons will eventually get damaged. The engine could overheat, and then you’re likely looking at a complete engine rebuild. Don’t run your motorcycle without its air filter, period. Even running a dirty air filter is still better than no filter at all. The price of an air filter is peanuts compared to what it costs to rebuild or replace an engine. Enough said.

Can you use any oil on a foam air filter?

Nope. Foam filter oils exist for a reason. They’re usually mineral-based oils that don’t dry out like synthetic oils, which are great for lubricating engine parts but not so much for air filters. All foam air filters should be oiled for an increased layer of protection. Foam filter oils are specifically manufactured to penetrate the foam cells, leaving behind a residue that serves as a trap for contaminants. If you don’t oil a reusable performance air filter, contaminants are more likely to make their way into the engine. When oiling a foam filter, wait until it has dried completely and then evenly spray it onto the entire air filter.

If you’re curious as to which of our videos the screenshots used in this article came from and want to see a motorcycle air filter cleaning in action, watch the video below to see how to clean and replace a Kawasaki Vulcan 1700 air filter.