Don't do this to your 250r

[3 or die]

Im sick! This has been the best engine I've owned for my 3rd gen r. It's had about 5 good weekend rides at st joe, mo. I bent my counter shaft during a chain break, so when i pulled the jug look at this bull.http://i947.photobucket.com/albums/ad314/3ordie/f2d7f521.jpg
This
motor is stock, with stock pipe, and air box. Stock jetting too. The damage is significantly worse on intake side. That tells me jetting is fine. Lean conditions cause high exhaust gas temp. Now I'm thinking low quality oil, or dirt ingestion. I've had very good luck with Lucas products. I use Lucas semi synthetic. 2 stroke oil at 4oz per gallon(32:1). I suspect dirt ingestion and look what I findhttp://i947.photobucket.com/albums/ad314/3ordie/13b3921d.jpg
That's a swipe on the inside of a k and n filter. Allot of grit has went right on through it. You will never find a kn filter on my machines ever again. I bent a shift fork in my 500 this week, now this!

[SteveCZ28]

that k&n looks pretty dry. did you regularly clean and oil it???

[atc007]

Yeah those pleats should be red with oil,, K&N gets a bad rap alot,,some swear by them,some swear at them. I don't use them personally. There is just no way that grit could have got IN there,thru oil. It was dry. Happens to the best of us..

[Blown 331]

I only run foam filters. K&N's flow more air, they also flow more dirt. LOL. Maybe that filter was a little dry. But even properly oiled I would expect to see at least half that dirt.

[Scootertrash]

3rd Gen ATC 250R is 85-86 (87?), right?

So correct me if I'm wrong here, but isn't the inside of the 250R filter the first surface that the incoming air contacts as it enters the air box?
Here is a pic of an 85-86 air box intake opening:

33808

So the dirt on the inside of the filter in your pic is dirt that the filter stopped from getting into your engine.

Hard to tell from the pic, is that a tapered style K&N with an closed end?
Was the filter oiled like it's supposed to be?

What does the inside of the air box look like?

[Scootertrash]

3rd Gen ATC 250R is 85-86 (87?), right?

So correct me if I'm wrong here, but isn't the inside of the 250R filter the first surface that the incoming air contacts as it enters the air box?
Here is a pic of an 85-86 air box intake opening:

150688

So the dirt on the inside of the filter in your pic is dirt that the filter stopped from getting into your engine. That is if you are running an air box.

Hard to tell from the pic, is that a tapered style K&N with an closed end?

Was the filter oiled like it's supposed to be?

Are you running an air box with a lid? Or just the filter?

If you are running an air box, what does the inside of the air box look like?

[Louis Mielke]

I'm not sure where you got that pic from but there's no way that could be installed right. The inside of the 250r filter is sealed in the intake track. That dirt is on the inside of the filter where it shouldn't be. Scootertrash do you own a 250r?

http://www.supermotors.net/getfile/618954/fullsize/p1010778.jpg

Here's what his K&N installed should look like. Dirt should be on the visible surface, not on the inside.

[250rAL]

That dirt didn't get in through a correctly oiled filter. Either it's dry or was leaking at the mounting area. Mine always has a light film of oil inside and there is never any dust in that oil.

[yaegerb]

I am with Blown331 on this one.

I USED to run K&N on my bikes. They are great for cars and a really good filter, but in my opinion they aren't good for very dusty, sandy, small particulate situations. I only run a heavily oiled UNI filter now with an outerwear. That setup seems to work really well.

[KASEY]

were you running an outerware??? those stop 90% of that grit,,,,

[Scootertrash]

[QUOTE=Louis Mielke;1142470]Scootertrash do you own a 250r?



Nope, I don't . Which is why I said "So correct me if I'm wrong here." ;) In retrospect I could have said something like: "I don't own a 250R but......" Now that I see how the whole intake tract is set up, I understand how the dirt is on wrong side of the filter.
What I don't understand is how there could be so much.

The pic was from another website, the snorkel/tube is just not attached to the air box

Thanks for the clarification on the complete set up.:beer

[kb0nly]

Toss the junk K&N and get a foam filter, problem solved. I have seen plenty of trashed trikes, bikes, and even car engines from dirt ingestion caused by a Kill & Nuke filter.

I do love when people put on a oiled Kill&Nuke and take out their $150-$300 MAP sensor and then complain about check engine warnings and driveability problems after about 20-50 miles of use. Usually its oil on the MAP sensor that causes bad readings, you can clean a MAP sensor despite what others may have told you, but it reduces the life of the sensor immensely. A little brake cleaner works, carb cleaner leaves some residue the good brake cleaners are meant not to leave any residue that could compromise braking. But its still a temp repair. With a correct filter the MAP sensor will darn near last the life of the engine in normal use conditions, but put on a Kill&Nuke and its done for in no time.

I know lots of people like them, and they always use the excuse "you didn't oil it right" but i have taken the directions from them and did it to the T and they still let a lot of dirt through. Increased airflow means less restriction, duh, that also means larger particles can get through. If you still insist on running one of these gimmick filters get the prefilter, but honestly if your going to run a K&N and a prefilter to make it a decent filter you might as well just put the correct foam filter on to start!

[Dirtcrasher]

I don't care for K and N either. Take off your airbox lid off, oil up a UNI (spray oil is great!) and I doubt you'll lose a ton of power.

The outerwears are a must for K and N!!

[tecat-z]

I've never trusted K&N's claims. Weather on the street, and especially in the dirt where fine dust particles are engines worst enemy. Seen many engines sign off early due to what people read. I run UNI dual stage filters exclusively. Lotsa open area with fine porus cells to trap nearly everything. K&N's simply can't match the protection by design.

[Scootertrash]

So on the dual stage UNI filters do you oil both filters or just the outside one?

[fabiodriven]

It's been discussed here many times before and I always have the same answer. K&N's have absolutely NO BUSINESS being anywhere near dirt. Run em in your cars or on your street bikes all you want, but you run em in the dirt and this will happen every time. They have no business selling K&N's for off road use IMO.

[4x4van]

Lotta hating going on here, but I'm gonna jump in anyway. Anyone who doubts that properly oiled and installed K&N filters are not among the best, you're wrong. No good for dirt? No good for sand? No good for silt, dust, or grit? Wrong. Ask anyone at Glamis with a $100,000 sand rail. Ask any desert racer with a 5000HP motor in their truck that must contened with 1000 miles of the dirtiest, sandiest, siltiest, grittiest terrain on the planet. The vast majority of them use K&N. Yes, I've seen the so-called "comparison tests" online. Sorry, I don't buy everything I see/read on the internet; I have my own experience to go by.

I raced motorcycles in the desert for many years. I grew up riding in the SoCal deserts. EVERY motorcycle/ATC/ATV I've ever owned in the 46 years I've been riding has been fitted with K&N. I have never seen even a tiny amount of dust inside any of my K&N filters. Ever. The K&N in the OP's post WAS NOT OILED or INSTALLED correctly, or it would not have ended up like that. Of course, it could also be a different brand, a K&N "lookalike".

Fouled MAP sensors? The K&N was likely "over-oiled". Dirt/dust getting through? "Under oiled", damaged, or not mounted tight. The K&Ns flow more air, not because it also allows dirt through, but because it has 5-10 times more surface area than a foam filter. Do the math. That is why desert racers use them; not only do they keep dirt out of a $50,000 motor, but they will last an entire 1000 mile race without clogging. Changing out a dirty air filter during a race takes time, and even seconds can make a difference. But that additional surface area also means that it is not as easy to oil correctly and get all of that surface area saturated without over-oiling. With a foam filter, it's easy to pour/spray on the oil, squeeze it in thoroughly, and you're done. Can't do that with a K&N. You have to take your time and make sure every pleat is saturated, all the way to the inside, without over-oiling it. Foam filters are like the "filters for Dummies"...very easy to do right. K&Ns are not for everyone, but to "claim" they let dirt through or that they shouldn't be used anywhere near the dirt is flat wrong. K&Ns were "born" in the dirt, and were used for decades before they ever became available for street vehicles.

[fabiodriven]

^^^Whatever. Bring your stuff to New England with a K&N on it. Two separate occasions I've had my carb on my R suck dirt through a K&N, real world, hands on experience. As a matter of fact, my R now has a lovely piston slap that can be attributed directly to that wonderful K&N so you're not telling me anything.

[Mosh]

First of all I can't take anymore of this.... It's M.A.F sensors that are effected, and cleanable. They don't lose any life from cleaning them unless you use some cheap autozone carb cleaner crap. That's cars anyway. And if you can find a way to clean a M.A.P sensor then you will be rich.

Second of all, I ride in some of the dustiest, muckiest conditions. I ran a k&n in my 96 shee for 6 years with only one maintenance rebuild. My wifes shee has had her engine in for 10 years on a k&n, and my 250R's, 2 out of 3 run them with over 3 years on the engines easily. My wifes R does run a uni. The failure you experienced is not from 5 rides of dirt sucking through the filter. More than likely it was sucking in somewhere else.

[Blown 331]

All the high horsepower and high dollar vehicles being talked about above are not made for longevity. I don't think anyone is disputing that K&Ns make horsepower, but there is a trade off.

[oldskool83]

id run a foam honestly. 5 rides is not nuff to kill the piston. i run K&N on street bike sonly box in non modded air boxes. if your running with alid off on your 250r maybe its eating too much dirt. id run a foam filter with a prefilter lid. i think they make them for the 250rs.

[badass350x]

LOOK I will say this much,, We own and race 2 of robby gordons older race trucks (GREERS) to some of you that might know the name,, Guess what he runs on them???? Do a search on youtube look at the desert,dust,sand,mud that these trucks are run in and tell me these K&N filters dont work for DIRT???

[Dirtcrasher]

So on the dual stage UNI filters do you oil both filters or just the outside one?

I believe the dual stage is in reference to the 2 different size pores in 2 layers of foam. Yellow on the inside, red on the out.

I clean them in gas, shake it off and bring it in for some Dawn and hot water. Once a year they also enjoy the spa :D

[El Camexican]

For the record I’ve never tried running a k&N on an off-road bike due to things I’ve read about them VS foam filters and thanks to a sensor issue on my F150 I’ll never use them on a car or truck again, but I do have one on my GSXR 1000 which has a straight shot ram air set-up. A couple years back I got caught in a sand storm in Coahuila and was driving at high speeds for over an hour through fine sand silt. I was sure my engine was going to be ruined, but when I pulled out the filter the “clean side” of the air box was spotless. I sprayed a little WD40 of a white paper towel and wiped everything and didn’t pick-up any dust at all. When I cleaned out the filter there was all kinds of sand in the pleats, but nothing seemed to have gotten through. I suspect generous amounts of oil I use were what made the filter work so well. I was coughing up crud for a couple days and I was breathing through a cloth while riding, so say what you will, well lubed K&N's work with dust.

[3Razors]

Like I've said before..K/N is nothing more than a very thin oily sock between two wire mesh screens. Also to the people that defend them, think about it...if they are so great then why is a outerware necessary for them to stop the fine dirt? That should be a red alert to people that they allow more particles through in the first place.

As far a maximum dirt stopping ability it goes..paper, foam, fabric (K/N) elements in that order from best to worst.

On the flipside for maximum airflow it goes..fabric, foam, paper.

Its simple physics but for some people just can't seem to grasp it. That fine silica passing through a K/N wreaks absolute havoc on cylinder walls and pistons. I've worked on 100's of bikes and with K/N equipped ones run in heavy dusty areas you can always pull the filter and run your fingers inside the intake tube and feel grit along the walls. The outerware does help but then those start to get old/torn and the elastic loosens up holding it tight which lets in more sand.

Dual stage foam has proven itself time and time again that it gives the best balance of high airflow and dirt stopping ability. Want more flow?? Just get yourself an even larger foam filter that has more volume for more airflow. And if you run no airbox with a clamp-on foam filter you can add a outerware on those aswell to aid in keeping the foam from clogging up. When dirt hits a outerware it more or less just falls off instead of passing through a fabric filter or getting stuck in foam filter.

K/N has its purpose for certain street applications and offroad drags, but that its imo. You see them on rails and trucks at the dunes because of the stiff metal design makes them easy to mount on custom motor applications. BUT also notice that most also run some sort of outerware of foam wrap over the top. Because they suck too much grit without added protection.

K/N's are a sore point with me as I've seen more than my share of motors toasted by them. Just sad to see motors not last as long as what coulda been.

[4x4van]

Whatever, I guess Robby Gordon doesn't know what he's doing? Desert racers are not stupid, and they are not going to do something that will damage or destroy a $50,000 engine. 1000 miles in the worst desert conditions possible...in order to finish first, you must first finish. And these guys at Glamis running their $100,000-$150,000 buggies are not rebuilding their engines every season. As I said, I've run exclusively K&N on desert races bikes and my ATCs ('85 250R, open airbox, no outerwear...the first mod I made when I bought it brand new 28 years ago...how's that for "longevity"?) for 43 years now, (outerwears are not "necessary", but they do increase the time frame between cleanings by allowing the larger pieces of dirt to drop off rather than being caught in the filter medium), and I've NEVER, I repeat, NEVER had dirt or dust get through any of them.

For all of you that keep insisting that "physics" proves that K&N must allow more dirt through since they allow more air through, you need to go back to college and take a physics course. As I've already pointed out, it's called "surface area". The pleats in a K&N provide 5-10 times more surface area than a foam filter, that's where the additional airflow comes from...If you increased the size of a foam filter 5-10 times, you would get more airflow, right? Does that mean more dirt allowed through? No, it doesn't. It's not rocket science.

K&Ns are a sore point with me as well, but only because of the misinformation that many swear by. I grew up riding and racing in the desert. I grew up using K&Ns. I will never use anything else for off-road, because they are the best. I know it because I pay attention to what desert racers use. I know it because I pay attention to what duners use. And I know it because I've actually tested it, in real world conditions, over 43 years. But I am also intelligent enough to understand WHY they work, HOW they work, and that they MUST be installed, oiled, and maintained correctly.

For those of you who insist on foam filters, fine, I'm not going to tell you not to use them; they work fine. But a properly oiled & installed K&N filters just as well, provides more airflow/HP, and will last 5+ times longer between cleanings.

[3Razors]

Whatever, I guess Robby Gordon doesn't know what he's doing? Desert racers are not stupid, and they are not going to do something that will damage or destroy a $50,000 engine. 1000 miles in the worst desert conditions possible...in order to finish first, you must first finish. And these guys at Glamis running their $100,000-$150,000 buggies are not rebuilding their engines every season. As I said, I've run exclusively K&N on desert races bikes and my ATCs ('85 250R, open airbox, no outerwear...the first mod I made when I bought it brand new 28 years ago...how's that for "longevity"?) for 43 years now, (outerwears are not "necessary", but they do increase the time frame between cleanings by allowing the larger pieces of dirt to drop off rather than being caught in the filter medium), and I've NEVER, I repeat, NEVER had dirt or dust get through any of them.

For all of you that keep insisting that "physics" proves that K&N must allow more dirt through since they allow more air through, you need to go back to college and take a physics course. As I've already pointed out, it's called "surface area". The pleats in a K&N provide 5-10 times more surface area than a foam filter, that's where the additional airflow comes from...If you increased the size of a foam filter 5-10 times, you would get more airflow, right? Does that mean more dirt allowed through? No, it doesn't. It's not rocket science.

K&Ns are a sore point with me as well, but only because of the misinformation that many swear by. I grew up riding and racing in the desert. I grew up using K&Ns. I will never use anything else for off-road, because they are the best. I know it because I pay attention to what desert racers use. I know it because I pay attention to what duners use. And I know it because I've actually tested it, in real world conditions, over 43 years. But I am also intelligent enough to understand WHY they work, HOW they work, and that they MUST be installed, oiled, and maintained correctly.

For those of you who insist on foam filters, fine, I'm not going to tell you not to use them; they work fine. But a properly oiled & installed K&N filters just as well, provides more airflow/HP, and will last 5+ times longer between cleanings.

I'd say you need to go back to college. I have a college degree thank you. Surface area is not whats important in stopping dirt flow. The material thickness and its "porosity" is what determines what particles are allowed to pass through. Take a 6 inch square dual stage foam filter and a 6 inch square K/N element bench tested with a vacuum and sprinkle varying thickness grades of dust and the K/N will let more dirt through every time. A name brand foam filter has a good 2 inches of material thickness that dirt has to try and get through, compared to the 1/8 inch of a K/N its a no brainer what stops more dirt. This has been confirmed numerous times independently by the likes of Cummins, Amsoil, ect.

I could care less what Robby Gordon uses. I'll stick with what the 1000's of engineers have tested at Honda, Yamaha, Suzuki, and Kawasaki combined use and that is oiled dual stage foam for the factory teams.

[fabiodriven]

I can respect the opinion of someone who has used something and had good results with it. I'm sure 4x4van feels as strongly as he does because of his own personal experience with this product just as I feel as strongly as I do because of my personal experience. I've experienced it personally like I said. Twice a carburetor filled with mud and now a piston slap because of it, also like I said.

The dunes and deserts are a far cry from the mountains and mudholes of Massachusetts and New Hampshire.

[4x4van]

I'd say you need to go back to college. I have a college degree thank you. Surface area is not whats important in stopping dirt flow. The material thickness and its "porosity" is what determines what particles are allowed to pass through. Take a 6 inch square dual stage foam filter and a 6 inch square K/N element bench tested with a vacuum and sprinkle varying thickness grades of dust and the K/N will let more dirt through every time. A name brand foam filter has a good 2 inches of material thickness that dirt has to try and get through, compared to the 1/8 inch of a K/N its a no brainer what stops more dirt. This has been confirmed numerous times independently by the likes of Cummins, Amsoil, ect.

I could care less what Robby Gordon uses. I'll stick with what the 1000's of engineers have tested at Honda, Yamaha, Suzuki, and Kawasaki combined use and that is oiled dual stage foam for the factory teams.

Surface area is what allows the increase in airflow. Oiled gauze is "less" porous than oiled foam. Foam filters are generally not "2" thick, but more like 1" (yes, still more than a K&N's 1/4", but the multiple layers of gauze are less porous than foam. Honda Yamaha, Suzuki, and Kawasaki use foam because of cost. Their factory teams ride on prepared man-made tracks that are watered and groomed; very little dust.

K&N filters have been used for decades, and were "born" in the dirt. They are the leading performance air filters for a reason. If they were responsible for "100s of engine failures" as some continue to claim, they would not still be on the market, much less #1.

To each his own. I'm not going to continue this argument because there are such strong opinions on both sides, it's a losing argument for all. I will continue to use what works for me, you continue to use what works for you. As I've said, I would never tell anyone NOT to use foam, it works perfectly fine. But so does K&N if used correctly.

BTW, 3Razors; I love your signature! 2-strokes forever!!!

[ATC-Eric]

Say what you want about either. What I know is that sometimes people forget to oil, and maintain filters. I choose a foam filter because they are "idiot proof." A dirty Foam filter chokes an engine down and wont run. A dirty K&N is a free for all for dirt and grit to get through.

[4x4van]

Say what you want about either. What I know is that sometimes people forget to oil, and maintain filters. I choose a foam filter because they are "idiot proof." A dirty Foam filter chokes an engine down and wont run. A dirty K&N is a free for all for dirt and grit to get through.
???

Actually, a dirty K&N (oiled) is no different than a dirty foam filter (also oiled); both will choke an engine down. It just takes alot longer for the K&N to get to that point (surface area, remember?).

But you're right, foam filters are pretty much idiot proof; easy to clean and oil. K&N takes alot more time and careful attention to properly clean & oil.

Oops, I said I wasn't going to continue this...sorry.

[3Razors]

Surface area is what allows the increase in airflow. Oiled gauze is "less" porous than oiled foam. Foam filters are generally not "2" thick, but more like 1" (yes, still more than a K&N's 1/4", but the multiple layers of gauze are less porous than foam. Honda Yamaha, Suzuki, and Kawasaki use foam because of cost. Their factory teams ride on prepared man-made tracks that are watered and groomed; very little dust.

K&N filters have been used for decades, and were "born" in the dirt. They are the leading performance air filters for a reason. If they were responsible for "100s of engine failures" as some continue to claim, they would not still be on the market, much less #1.

To each his own. I'm not going to continue this argument because there are such strong opinions on both sides, it's a losing argument for all. I will continue to use what works for me, you continue to use what works for you. As I've said, I would never tell anyone NOT to use foam, it works perfectly fine. But so does K&N if used correctly.

BTW, 3Razors; I love your signature! 2-strokes forever!!!

We can agree on that, if there is one thing that would make the world a better place would be a 2 stroke revival!

On the porosity issue of K/N, from what I've seen with used ones washed a few times is that if you hold them up to the sunlight you see tiny holes that allow grit to get through, do the same test on the inner layer of a foam filter and no holes.

[cbx1170]

Worked as a flat rate tech and mech for years. I cant even say a foam is better than K&N or vice versa. A properly sealed intake with a good prepped filter is needed no matter what is used.... any type or brand. I have seen a lot of damage. Personally I will say this. On my 85-86 R's I looked very carefully at the clamp setup of a stock filter. It had a steel support inner screen/ring that clamped on both sides of plastic airbox flanges stock... for a reason. It made a positive seal. I tried to clamp on a K&N on a spare airbox. I inspected from both sides inside and out. It distorted the plastic to the point of collapsing or wrinkling or coning the plastic tube. I was not impressed. Thats why I did this.
http://www.3wheelerworld.com/showthread.php/120634-Atc250r-k-amp-n-filter-support-rings-made-easy

I am watching all of my piston/bores closer here in desert to see really if one type is better than the other. Very closely.
Obviously K&N if you hold up to a light bulb and you see any light speckles its really bad. I got one on a 500 that does not look bad but may be bad but I first need to verify intake was actually sealed.

[4x4van]

Worked as a flat rate tech and mech for years. I cant even say a foam is better than K&N or vice versa. A properly sealed intake with a good prepped filter is needed no matter what is used.... any type or brand. I have seen a lot of damage. Personally I will say this. On my 85-86 R's I looked very carefully at the clamp setup of a stock filter. It had a steel support inner screen/ring that clamped on both sides of plastic airbox flanges stock... for a reason. It made a positive seal. I tried to clamp on a K&N on a spare airbox. I inspected from both sides inside and out. It distorted the plastic to the point of collapsing or wrinkling or coning the plastic tube. I was not impressed. Thats why I did this.
http://www.3wheelerworld.com/showthread.php/120634-Atc250r-k-amp-n-filter-support-rings-made-easy

I am watching all of my piston/bores closer here in desert to see really if one type is better than the other. Very closely.
Obviously K&N if you hold up to a light bulb and you see any light speckles its really bad. I got one on a 500 that does not look bad but may be bad but I first need to verify intake was actually sealed.
Yes, I agree; the stock mounting flange on the 85-86 250R leaves a lot to be desired when using ANY aftermarket filter (which could in fact explain the pics in the first post), both on the filter side as well as the boot side. I have added a piece of dense closed cell foam on the opposite side of the airbox pressing against the filter to keep it in place (on both my Rs), and that has served me well for many years, but once I saw that post of yours... Now that is a great idea. I have a small propane tank and as soon as it is empty, it will be sacrificed for the greater 3-wheeler good!...Thank you for that link. Awesome idea and tutorial!

BTW, while foam filters can be effectively cleaned in gas, K&Ns can be damaged by using gas as a cleaner. Actual K&N cleaning products SHOULD be used; my K&N is still in great shape, even after 27 years of use. There are no "thin" spots where light shows through, but I clean carefully with K&N cleaning products, not gas, and re-oil carefully as well.

[Mosh]

Ok..Lets try to put this to rest and I am being totaly honest about everything here as I have often wondered what was better for dirt control. I am going to do 2 side by side pic series...

Both trikes are 85 R's. Mine runs K&N, hers, runs a UNI..We both run Dirtcrasher airbox support rings to keep the box from buckling when tighteneing the filter.
These are from our last ride 3 weeks ago at Wellsville. I lead..She follows..I naturally kick up more dust for her, and it was dusty.

My K&N properly oiled and sealed..This was AFTER the ride, but it was properly serviced before the ride..Both trikes.
http://i100.photobucket.com/albums/m40/cosmicquads/DSCF1001.jpg

http://i100.photobucket.com/albums/m40/cosmicquads/DSCF1003.jpg

http://i100.photobucket.com/albums/m40/cosmicquads/DSCF1002.jpg

http://i100.photobucket.com/albums/m40/cosmicquads/DSCF1004.jpg

Now.... her UNI system..Same bike 85 R.

http://i100.photobucket.com/albums/m40/cosmicquads/DSCF1005.jpg

http://i100.photobucket.com/albums/m40/cosmicquads/DSCF1009.jpg

http://i100.photobucket.com/albums/m40/cosmicquads/DSCF1007.jpg


I DO NOT run an outerware..We both rode identical trails, her being in behind me getting more dust from me in front of her. We dont run lids. I have done 3 of these tests side by side and forutunately this debate came up at a time where both of my trikes were in identical conditions and they needed serviced..I service filters after EVERY ride..
You make the call...

As I speculated before..I have run both filters on different machines and NEVER blown a engine..Let alone seen scoring like this guy has the (OP)..The dirt came from poor sealing I believe if that is indeed what fried his piston..I can see it in his airbox deformation pics he posted that he suffers from what all of us do on 30 year old stuff.. Forutnately for me I got DC airbox rings...So maybe you guys can pursuade him to do another run..He had them for sale awhile ago, but he didnt get much support for them.

[3Razors]

Mosh that is a good test for your riding type and area. Is there much silt dust where you ride? In some parts of the desert here you hit silt/loam washes and it hovers in the air so bad that you can't see 10 feet in front of you. Also on the 85-86 250R where most of the grit will accumulate is farther down the belly of the intake tube near the carb. And the airbox support rings are a MUST have on that model.

[Flyingw]

I think the main issue with the K&N filters is one of a design standpoint and the other is maintenance standpoint. The K&N improperly serviced fails to filter out small and fine dirt particals it was designed to whereas the foam filters have a naturally tighter pores that even if they are improperly serviced still retain the ability to filter out even small particals. With that said, is one better than the other? yes and no. Like Mosh pointed out in his filter shootout, he services the filters AFTER EVERY ride. I think this is key here. How many of us take our air filters for granted.....I will admitt I do but I dont do allot of sand riding anymore. This is the other part of this debate. What terrain are you guys riding in? Primarly sand, trails, mud. You So Cal and AZ boys....have to deal with sand and with sand comes silt. Silt if not properly filtered will destroy a motor, bearings etc because the particals are so fine. it gets in everywhere but the boys riding trails and back roads dont deal with baby powder silt so much.

I've used foam air filters all my life and having spent my youth in SO Cal riding the desert never had problems but back then I did service my filter before each ride and during the weekend but I was riding 2 wheelers back then but the basics are the same no matter what you ride. Now I ride mostly trails and mixed terrain but I still don't service my air filter as often as I should. The outerwear socks do a good job at pre-filtering the air but they do choke airflow to some extent but if riding in sand, they should be installed for that added level of protection. When I was in the Air Force. I spent allot of time in Saudi and we had Kawasaki Mules to run around in. We were always sending wheel bearings over there to keep them running bacause the Mules live in a sandy dirty enviroment 24/7 and it took its toll on those machines constantly.

The other thing mentioned in this thread is the airbox and how well its sealed and how well the filter is fitted and tightened to the flange in the airbox. You can have the best air filter in the world but its useless if the airbox leaks (for those of you running lids) and likewise with the filter mounting flange. I have this stuff called petrolatum. Its used to condition and lube orings and seals. Generally a great product to have around but I also use it to lube the filter flange in the airbox. When I tighten it down, I dont torque it to 100lbs. Just snug enough to keep the filter securely attached to the flange. The petrolatum provides a good seal at the flange so any air coming in to the carb will only come in through the filter. Vaseline or something along those lines will provide the same effect.

So the lesson here no matter what filter you use is...... Service your filter frequently. Wash and re-oil the element before each ride and if on a long weekend, spend a few minutes in the middle of that weekend to clean and oil your filter or even daily if the conditions are especially dirty.

[Mosh]

Glad some of you like the comparison test results. Of course I am not and authority on the matter, and conditions were not set in a controlled environment, but it is a pretty conclusive test.

We had some discussions on this before and 3 razors bet his stakes that the K&N would actually show more dirt. after the 3 tests I have done, the K&N does let a little dirt through moreso than the UNI. However, I probably should run an outerware and retest to see if that helps the K&N.

Here is a link to what the airboxes let in without the support rings.
http://www.3wheelerworld.com/showthread.php/121265-Dirtcrasher-s-Airbox-Support-rings!!!-250R-350X?highlight=air+box+rings


3 razor's..our riding out here is primarily clay hard pack that turns to literal talcom powder consistency in dry conditions. The top of the clay gets chewed off into a fine silt like mix. It usually creates a fair amount of dust in dry conditions out here. I could try to find some pics, but even so, any MX we have done we usually are mid pack and that creates alot of dust from 10 other riders.

[250rAL]

Mosh, your filter looks white. Are you using other than K&N oil which is bright red?

[Mosh]

Mosh, your filter looks white. Are you using other than K&N oil which is bright red?

No the filter is over 10 years old. That is more dust you see, but the camera flash made it look white. It is actually brownish pink. I only use K&N oil on that.
The UNI gets PJ1 foam oil.

[ZZTOP]

Best thing you can do with a K&N is run an outerwears or a knee high stocking to cover it. It helps weed out san and smaller particles that can escape the K&N filter /.

[4x4van]

No the filter is over 10 years old. That is more dust you see, but the camera flash made it look white. It is actually brownish pink. I only use K&N oil on that.
The UNI gets PJ1 foam oil.
Even the inside of your K&N looks white; it should be red, since there shouldn't be any dust there to throw off the color. I'd like to see that same pic without the flash; 'cuz it still looks dry to me.:confused:

[Mosh]

Even the inside of your K&N looks white; it should be red, since there shouldn't be any dust there to throw off the color. I'd like to see that same pic without the flash; 'cuz it still looks dry to me.:confused:Like I said..I am not an authority on the matter. But if you doubt I do things the correct way, you can dial up youtube and burn the next three days of your time watching "OTC trike MX racing" and see me hammering my engine for the last 3-4 years without a rebuild.

[4x4van]

Like I said..I am not an authority on the matter. But if you doubt I do things the correct way, you can dial up youtube and burn the next three days of your time watching "OTC trike MX racing" and see me hammering my engine for the last 3-4 years without a rebuild.
It's all good, dude, I'm not doubting you, You obviously have been riding/wrenching a long time with a variety of bikes. I'm just saying that it looks dry, that's all. Maybe, as you said, it's the flash; that's why I said I'd like to see the same shot without the flash.

I typically go at least 2, sometimes 3, full 3-day weekend trips in the dunes between cleanings on my 27 year old K&N. I've never found any dirt/dust inside the filter or boot, and it always looks red on the inside, even if the outside is brown, tan, white...whatever color dirt I've been riding in. But then, I've never taken a "flash" pic of it, either...perhaps mine would also look white under the glare of a camera flash.

[Dirtcrasher]

Well, they never got much of a response so I'm glad Mosh got some and I'll make Brrcuda and DEEPA a set. Large aluminum tubing is not cheap nor is the machine time.

Ever tighten you filter and watch it pull away and fall off? Thats why I made them...........