What are the Different Types of Air Filter Elements, its Roles, and Periodic Inspection Method!

The air filter element attached to the entrance of the air cleaner case is an important part of the air cleaner that removes dust and dirt from the air. If the element, which is made of sponge or non-woven fabric, becomes clogged with dirt, the amount of air intake will decrease and the engine will not perform as well as it should, so regular replacement is necessary according to the mileage. Also, if you have been driving in a dusty or dirty environment such as touring in the woods, it is recommended to check the element earlier than the specified period.

What are the risks of style-first air funnel specifications?

This is a type of air filter element with a sponge stuck on top of a mesh-like frame. When it was new, it was flexible enough to stretch when pulled, but over time it has started to come off in pieces. If the element is left unattended, the risk of it being sucked into the engine increases, so it needs to be replaced as soon as possible.

We all know that an engine needs air to run. Whether carbureted or injected, gasoline is mixed with the air being sucked in, and power is produced by explosive combustion after it is sucked into the engine as a mixture.

And just as we wear masks in our daily lives, it is the air filter element that removes dust and dirt from the air the engine breathes in. Just as it is reckless for hay fever sufferers to go without a mask during the pollen season, so too, for motorcycles, riding without an air filter in the intake system only shortens the lifespan of the engine and is an all-or-nothing affair.

Indeed, before the 2000s carburetor era racing machines did not have air cleaner boxes or air filters, but only funnels. However, this was only possible in the limited area of a race track, where engine maintenance was done frequently, but for the unpredictable driving conditions and the tens of thousands of miles of public roads, this is not a good choice, even if the goal is to increase power.

Some bikes may have run well for tens of thousands of miles on funnel specs, but that may just be a combination of chance and luck. There's a non-zero chance that even a few millimeters of sand will bite the intake and exhaust valves. With an air filter element, on the other hand, the chances of that happening are slim to none. While funneling a carburetor car has a lot of custom appeal, it's important to understand that there are risks involved.

As for the injection models, first of all, there are extremely few vehicles that have the styling benefits of funneling, and secondly, some models require sensors inside the air cleaner case to determine the injector delivery rate, so there are few changes to the funnel specification It doesn't seem to be common.
 

There are two types of bellows type elements: "dry" and "viscous

At first glance, it is difficult to tell the clear difference between a viscous air filter element and a dry type air filter element. If you look at it closely, it seems to be a little wet, but if the instruction manual or service manual specifies the viscous type, do not blow air.

The air filter element, which removes debris from the air, can accumulate dirt depending on the mileage and driving conditions. This will reduce the amount of air that can be sucked in, just like when the dust filter of a vacuum cleaner is clogged with dirt. Some vacuum cleaners have a cyclone type that does not change its suction power as dirt builds up, but motorcycle air filter elements do not have a cyclone type, so they must be inspected, cleaned, and replaced by the owner himself.

Your motorcycle's owner's manual or service manual should state the distance and duration of air filter element inspection and replacement, e.g. "Replace every 20,000 km". However, if your vehicle is in severe driving conditions where there is a lot of moisture, dust, and dirt, there may be additional instructions to check the air filter element for a shorter distance.

Maintenance methods vary depending on the material of the air filter element. The sponge type element, which can be cleaned and reused by applying filter oil, has been used until rather recently, mainly on trail models, but after a long period of use, the sponge itself can deteriorate and crumble into tatters. If you start the engine in such a state, pieces of the sponge can be sucked into the carburetor and engine and cause a malfunction, so it's important to take it out of the case and check the condition of the sponge, even if the mileage hasn't reached the replacement date, if it's been years.

Note that there are two types of filter paper type elements, the "dry" type, and the "viscous" type. The dry type uses a dry filter paper or non-woven fabric, which can be cleaned by blowing compressor air from the inside of the element to the outside if it gets dirty. The element is folded into a bellows shape with mountainous and valley folds, but since much dirt accumulates in the valley when viewed from the intake side, dust can fly out in a big way when air is blown.

In contrast, the viscous type has a special feature of oil permeating the element. Like the filter oil in the sponge element, the oil content on the surface of the element absorbs fine dust, but air blowing blows the oil away, so cleaning is prohibited in principle, and when the time comes to replace the element, don't hesitate to replace it.

Does a clogged air filter make the carb setting thicker?

After removing the air filter element, wipe the inside of the air cleaner case with a clean rag to clean it. Carbureted cars may have carb blowback, and if the oil level is high, such as a Keihin CVK without an overflow pipe, gasoline may accumulate in the case.

Just as a clogged mask we use can make it hard to breathe, a clogged air filter can prevent the engine from breathing as much air as it wants to. You can imagine that this will reduce engine power, but in the case of a carbureted car, the air/fuel ratio can change.

The carburetor is responsible for supplying gasoline based on the amount of air passing through the venturi, which is an air passage, but that gasoline is sucked out by the negative pressure generated in the venturi, rather than mechanically injected as in an injected car. When you open the throttle and the venturi opens, the engine tries to suck in the corresponding air through the air cleaner case.

However, if the air filter at the entrance to the case is clogged here, the engine won't be able to flow as much air as it needs, and the negative pressure on the venturi will increase, and that negative pressure will suck more gasoline out of the carburetor's float chamber than it needs. Squeezing the air inlet to thicken the fuel is the same thing as a choke mechanism to improve cold starting. If a rag placed near the air cleaner case is about to be sucked in and blocks the entrance, the engine will stop.

Even if it's not that extreme, if the air filter element is clogged, it will have a relative excess of gasoline as well as those, and the plugs will tend to get rash. If you check the condition of the plugs and the electrodes are smoldering, check not only the carburetor setting, but also the condition of the air filter element.

The sensors in each part of an injected car detect information differently depending on the model, but if the air intake air volume is reduced due to a clogged air filter element, the amount of fuel injected is compensated accordingly and the air/fuel ratio may not change. However, even if the plugs don't change, the condition of the air filter element is still important, because reduced airflow will naturally lead to a loss of power.

Some injected vehicles measure the pressure change inside the air cleaner case and reflect it in the fuel injection volume. In this case, it is also important to make sure that the seal on the mating surfaces does not come off or float when the element is placed in the case and the cover is installed.

On models where the crankcase blow-by gas is connected to the air cleaner case, there may be a translucent check hose at the bottom of the case. If there is a buildup of incoming oil in this hose, remove the air cleaner cover and clean the inside of the case and clean the inside of the hose as well.