[Hoiho]

Neither! Although when a opaque paper filter is blocked it's likely easier to see than deciding when an oiled cotton filter isn't working properly.. if you get my meaning.

[viczena]

I use K&N for all my bikes. It is easy to see if it is clocked. Brake cleaner, dry with presurized air, thats it. Once a year. Or every 6 month if driving in really dirty conditions.

[Hoiho]

I use K&N for all my bikes. It is easy to see if it is clocked. Brake cleaner, dry with presurized air, thats it. Once a year. Or every 6 month if driving in really dirty conditions.

No oil?

[viczena]

All my bikes have the case vent through the air filter. That is enough oil.

[Hoiho]

All my bikes have the case vent through the air filter. That is enough oil.

Interesting. Is that a fault or a modification?

[viczena]

Its normal.

[ace.cafe]

It comes down to surface area.
It won't matter if a filter is 99% effective if there is only one square inch of it.

If a K&N is a full size element with enough surface area to meet the engine's flow needs while filtering the air at 99%, then good. If not, then not good.

Most, if not all, of those "pod" filters that clamp on to the carb or TB are not even near enough surface area, nor do they provide enough free air volume inside the filter barrier for good throttle response or good atmospheric air pressure . If you look at them dirty, you can see that they flow mostly within the first inch, or so, of gauze.

A larger panel filter or round filter with plenty of surface area is much better, whether gauze or paper.

[viczena]

You are right, I always use full size filters.

Do you know if the special filter can for UCE 500 from Ace is still available?

[gizzo]

I have NFI about the filtering capability of K&N. I don't rate them because the ones I've looked at don't fit the airbox properly. My LS650 and my TRX850 both had them, both didn't fit. I replaced them with OEM filters. My daughter's WRX has one. It doesn't fit properly either.

I'm running the Ace airbox mod with paper filter. I've tried it with and without the element, doesn't make a scrap of difference. IME paper filters do just fine removing dust and reusuable filters are not worth the hassle to me (my dirtbikes, sure. Oiled foam. It's very dusty where I ride. If I were tootling through the Black Forest I doubt I'd even need an air cleaner).

My 2c, YMMV etc

[ace.cafe]

You are right, I always use full size filters.

Do you know if the special filter can for UCE 500 from Ace is still available?

Unfortunately, I had to discontinue that item due to parts supplier issues.
 

[Karl Fenn]

I think l would rather have a clogged paper filter than a reusable that could suck dust into engine accelerating top end wear.

[viczena]

i understand that you do prefer engines that do not work.

[Fred Gassit]

The test we are interested in is:
"ISO 5011:2020(en)
Inlet air cleaning equipment for internal combustion engines and compressors — Performance testing"

It's very difficult to find results pertaining to actual particle size that the various different filter constructions will capture, but here is one test (for a diesel truck rather than a motorcycle, but the test methodology is the same):



"Filtering efficiency is a measure of the filter’s overall ability to capture dirt."
" The course test dust has a specific distribution of particle sizes ranging from less than 2.5 microns to greater than 80 microns."

So, 99.93% efficient for an off-the-shelf AC Delco paper filter, and a pretty poor 96.8% for the K&N. That's a lot of crud getting through.

And a thought provoking personal opinion from master mechanic Shawn Smoak (jump to 2m30s):
TheSmoaksVlogs

[viczena]

With filters you always have to make a compromise. If you have a very efficient filter, less air comes through and it clogs up easily. Until nothing goes through. If you have a filter with less efficiency, more air goes through and the filter keeps open longer.

You can enlarge the surface of the filter, but you get to physical limits.

The difference between the best and the K&N filter is mere 3%.

The guy in the video never seems to have opened an engine. And inspected if this "grind" did some damage at all.

BTW: The efficiency is only one oft the test in ISO 5011. The others are equally important. And I have an idea which filter is the winner in the other categories. And there are even 3 different efficiencies in ISO 5011. Which one the graph shows keeps unclear. Most probably the initial efficiency. Determined after the addition of 20 g of contaminant or the number of grams numerically
equivalent to 6 times the air flow in cubic metres per minute, whichever is the greater.

[biscot]

I'm a bit confused - I have the DNA filter (and removed the snorkel in favor of the open filter with the DNA cover plate or whatever you call it).
Is this the same as the K&N filter? I don't care about the sound, or the supposed performance upgrade, I just want to know I'm giving my engine the optimum intake protection. I do ride on duscty roads, and clean and re-oil the filter at intervals. Would I be better off to go back to paper filters and just change them on intervals? It's not about saving a few bucks, just preventing premature engine damage.
Sorry if this is taking the thread off topic.