I agree with you on this. It's funny how one or two guys are claiming foam filters don't work yet. I just come from two different forums that have hundreds of members using uni filters on grizzlies and kodiaks for well over the last 10 years. Absolutely zero issues with dust getting by them and that's even with the Yamaha's notorious leaky air intake design over the last 5 years or so. A properly oiled uni and installed correctly will have zero issues.
Um.......Uni Air Filter
Still running thru the maintenance after the last trip. I should mention the first day it was crazy dusty. The second and third day brought morning showers which made for the perfect riding conditions.
I ran into a very similar situation years ago with the sport bikes. I guess deep down I wanted to like these filters.
Even though it was properly oiled and installed with a bit of grease around the neck/mating surface, there is evidence of dust making it past the filter media. Yup, kinda upsetting.
I will be sticking with OEM filters moving forward. They are reasonably priced enough, there is no reason not to.
Your Milage May Vary........I Guess
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I just did a valve adjust on a bike that was running a paper air filter, these usually have the best fine particle filtration. Still under that filter was a light coating of fine silt that made it through and would be sucked into the engine.
A very tacky filter oil on a foam filter will be more using the oil to do the filtering than the foam itself as the foam is simply only going to catch large particles. The super tacky fluids are a mess/pain to clean and apply some times but they are what has been found to protect the best in situations where fine sand can be sucked in. Also remember your intake is running similar to your best shop vac in the suction from the engine is great at higher rpms.
If you want to see how effective a filter is try and run a shop vac through it and see what you get past the filter. I have a K&N on my blast cabinet and then run it to my shopvac, when running glass beed there is plenty of times I have to clear the filter (which is good) but at the same time there is also plenty that gets through the filter into the shopvac.
On another note keep in mind filters also keep mice out (hopefully) and they will eat through a paper or foam type with ease if there is not a scrreen to keep them out or a oil they simply do not like the taste of. I just found this nest here on a customers bike (which is a first) so a reminder of the damage they can do as well as how small an area they need to be able to "get inside"
This is inside the steering head where they went in through the inside of the frame .
bottom picture is of the aluminum steering stem which the mouse piss has eroded to the point of impending failure.
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A very tacky filter oil on a foam filter will be more using the oil to do the filtering than the foam itself as the foam is simply only going to catch large particles. The super tacky fluids are a mess/pain to clean and apply some times but they are what has been found to protect the best in situations where fine sand can be sucked in. Also remember your intake is running similar to your best shop vac in the suction from the engine is great at higher rpms.
If you want to see how effective a filter is try and run a shop vac through it and see what you get past the filter. I have a K&N on my blast cabinet and then run it to my shopvac, when running glass beed there is plenty of times I have to clear the filter (which is good) but at the same time there is also plenty that gets through the filter into the shopvac.
On another note keep in mind filters also keep mice out (hopefully) and they will eat through a paper or foam type with ease if there is not a scrreen to keep them out or a oil they simply do not like the taste of. I just found this nest here on a customers bike (which is a first) so a reminder of the damage they can do as well as how small an area they need to be able to "get inside"
This is inside the steering head where they went in through the inside of the frame .
bottom picture is of the aluminum steering stem which the mouse piss has eroded to the point of impending failure.
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