I had more sand get through the foam then I did the K&N. With the foam I would have sand between the filter and the carb. Yes the foam filters were maintained and oiled well. In fact tried different types of foam filter oil. Did not have the sand with the K&N. One of the things that sold me on the K&N's over foam. That and the K&N was much easier to clean and re-oil. Don't know about really fine dust but with sand it seemed to me the K&N did a better job. When it comes time to replace the stock, I suspect I will go with the K&N.

By the way, sand going through foam filters is common. Had a dune buggy dealer tell me the same thing about foam.

 

How do you know the debris is not going through the K&N?
more airflow= less restriction......Correct?................

Paper traps dirt ,no question about that!!!!........I kind of like seeing the dirt "STUCK" on the paper filter...............Because it's not in the engine!!......Caper.......

 

Wipe the air intake between the filter and the engine and see what one gets. With two strokes there was always a bit of normal blow back through the carb and the oil would collect stuff. It takes very little to start slowing the air down. The oil on the K&N seemed quite effective at trapping and holding dirt, sand etc. Not sure how a paper and K&N would match for trapping and holding dirt before restriction. Add an outer wear to a K&N and suspect you would have a good filter will lots of air flow. Had one sport bike with the K&N with outer wear and the owner says the K&N just did not get dirty. In fact I should have thought of added outer wear sooner. If I remember correct the outer wear will not let water through while letting air flow.

If you are happy with a paper filter, by all means stick with it. I responded to this thread just to say, do not sell the K&N short. I was not a believer at first but experience has opened my eyes. They sure do have there application and do have positive benefit without a negative that I have seen, except the original cost. But that is offset with the first cleaning with using it over again.

 

Yes I agree with a sport bike.........I myself don't mind having some restriction if I know the filter is doing the job...........Everybody has a different view and it great to read them I hope they keep comming .........................I think I would use K&N filters for road use only pavement,or highway use..............Thanks ..........Caper............

 

Thanks for all of your input!

 

As the test stated, unless you are running wide open on a more or less constant basis, a K&N, or foam filter does not flow enough air over a stock paper filter to warrant the added costs. And neither filtered as well as a paper filter. I've used K&N filters before on several motorcycles, and on a Dodge truck, so I do have some experience with them myself.

If running up sand dunes wide open is what you do, then I suppose the K&N is the way to go for you. IF and only IF the small added power you get from a K&N filter is worth more to you than filtration. I'll take filtration anyday.

I'll bet the vents you cut in the airbox did more to allow more air into the engine than the K&N did. I'll bet if I switched the K&N out for a paper filter without you knowing, you would not know the difference. K&N's advertising has been very effective.

 

If water is going to continue to be a problem, shouldn't you snorkel your intake?

 

what the K&N does give you is reusability....you can pull it out, clean it, reoil it and put it back in....I can say on my race quad, YFZ450, it made a bunch of difference, on my SP800 I couldn't tell anything, but I still have it because i can clean after every few rides....you do have to be careful though on the oiled filters and a EFI machine, it will suck in some oil on a over-oiled filter and build up on the throttle plate in the throttle body and cause the idle to drop, just needs some cleaning with some intake cleaner to get it back up to correct rpm

 

Thats what I figure too. A K&N with an outerwear will hold up about forever only needing to be cleaned and the outerwear provides your extra filtering.

 

ask the dealer cuz a friend of ,mine put on a after market aircleaner (i think k/n not sure) and when he got high up in the mountains bike wouldnt run...dealer told him that the airfilter screwed up his computer efi settings.. to much air