k@n filters not good for 400ex

[markschevy]

i talked to pro fab today about a 416 kit and they said do not run a k@n filter becasue its scorches the cylinder walls more.Told me to run a uni with a oil base filter with foam.

[trailburner]

All I can say is what I've seen..I run a K&N [oiled properly] with a outerwear, And I've rode for hours when the dust was so bad I could hardly see the trail, took the filter off to clean it & the inside of the intake boot was SPOTLESS!!!works for me.......

[Glamis400ex]

That's BS, he probably gets a kick back for every UNI filter he sells. Maintain a K&N properly and it will be fine.

Scorch the walls..:huh That's a new one...

Glamis

I think he put the K&N filter were the piston goes...:eek: :huh

[markschevy]

he wasnt trying to sell me one he was telling me what they were seeing inside the engines when adding larger cubes

[dawzie]

We raced MX for a whole season with K&N and never once had any signs of dirt inside the air tube. Have never had an engine failure yet !!

[trx400ex]

There is some truth to what he said, and yes he does know what the **** he is talking about. The thing with KNs is that you have to keep them oiled good and you need an outerwear. They still do not filter as good as a foam based filter and i think that is proven. And by scoring the cylinder, i dont know if that was the term he used, but he probably means that the dust that slips by KNs will get in there and mess up your engine which it can and will if you let it. And in case you are wondering i run a KN the flow is unmatched and as long as you keep it oiled and prefiltered it will do a pretty good job. Ive found dust stuck to the inside of my intake boot before, but sometimes i dont clean filters as often as i should. I just think if you have a KN a prefilter (outerwear) is a must. It keeps dirt from filling up in the folds and keeps water running off. ALso i dont run an airbox and if you dont you run a much higher risk of getting dust sucked throught the filter bc it is sucking it in above the rear tires and behind the front where it is kicked up. With a snorkle it is much more protected and less risk.

[phatswinn]

and on really dust times in the summer the dust actually helps it filter by cloting the dust up so ur not supposed to actually clean itwhen its really really fine dusty out u just bang the dirt off and re-oil it, thats one of my tricks, ive been using k&n in all my vehicles for 10 years and have had absolutly no problems with them, i dont run a prefilter either

[roostu]

That guy is full of it. I agree that a K@N lets more particles through if not maintained, but the amount that is needed to "scorch" a cylinder wall or "dust" a cylinder would take a LONG time. If you keep your K@N in good condition and oiled properly it will give you trouble free operation. I personally use a UNI everywhere except the dunes just so I don't have to clean and oil the K@N every 2 or 3 rides. (I live in Arizona were it is VERY dusty)

Stick with a foam type if you don't have the time or patience to clean it regularly.

~Roost-U

[400exredrider]

i run a K&N on the Mx track with no lid on or outerwear i have a 465 and it hasent harmed it at all.....even when i get tons of mud in the air box....:devil shouldent be but hey......also if you gut some air filter oil mixed with water and mix it up good or it wont work and pour it through your airbox and the dirt will stick more to the sides of your air box then in your filter.....just a recomedation but dont doit if you dont know what your doing......:blah

[Glamis400ex]

400exredrider,

Another trick is to spray the inside of your airbox with chain lube to attract the dust. Of coarse this wont work with the chain wax and that sorta stuff, but the regular sticky chain lube works good for that.

Glamis

[Martin Blair]

Thats a good idea i might try that, wht aobut just some regular motoer oil? Or diff grease that like 90 wieght.

[TORO1968]

I must say that that sounds like a load of BS... Yes, a K&N will let more particulates through if not maintained when comparing it to a properly oiled foam filter like a UNI, but there is no way in heck you could attribute a K&N filter to causing cylinder wall scoring. There are many other factors that need to be considered when dealing with engine wear, including load, operating conditions/temperatures, oil condition and level, air/fuel ratio, etc.

How well do you think a UNI filter would work if it wasn't oiled? Same principle, so these must be junk too...

Yes, dirty air is bad for your engine, but saying that using a specific type of air filter will mess up your cylinder walls on an engine is rediculous. That's like saying Mobil 1 caused an engine to get worn out because the oil broke down, but failing to recognize that the oil needs to be changed regularly to prevent this from happening.

I hate it when someone is so biased towards one brand or type of product that everything else comparable to this brand/product is considered "complete junk". I don't take anybody's word for anything if they can't back it up with some credible evidence or research.

Just my honest opinion though... K&N gets my vote! I've never had a problem with any of mine on my cars and truck. The key is proper maintenance.

People, do your homework before making unsubstantiated claims, and keep those filters clean and oiled, or its cylinder boring time!!!

Think of how many bores and re-sleeves will need to be done throughout the lives of our so-called "bad" filters with their 1,000,000 mile warranties! :D

Long live the K&N!

-Jordan

[JOEX]

Well said Jordan!:macho

Joe

[Castor-426ex]

ive had the same k&n filter on my ex since 2000....my damned cylinder walls still tickle my pickle

in otherwords...somebody is sponsored by uni:D

I think some of you guys are getting confused, yes confused cause you say in one sentence that the K&N doesnt stop as much fine dirt or sand and then say that it isnt gonna scortch the cylinder walls.

Now think of what were talking about here. The sand that can and DOES get past the K&N will then get into the cylinder and thats where it gets interesting.

So just like a very fine sand blaster the sand will "sand" the inside of your motor. Will it cause it to make scratches in the cyl wall or valves? Sure it will, sand is abrasive and will wear into aluminum no doubt.

Will it be noticable or will you be rebuilding every 6 months, no way. You could run with this filter for years and wouldnt even notice the compression drop cause its so gradual. But it does happen and if you take a 2-3 year old motor and do a comp test you would see a difference (and yes even v/s a motor with the foam filter) but then if you wanted top performance you would be looking at a new piston by that time anyhow.

so its allmost not an issue except for the guy who is looking to keep his machine for many many years without any internal work, and thats not the guy looking to get every ounce of power from his motor and doesnt need a K&N in the first place.

Remember that I am considering that the K&N is properly cleaned, dryed and oiled reg. not every six months and then oiled when wet and forgotten again :)

[Newbie400ex]

To score a cylinder wall would take some pretty big particles. I'm sure the K&N will filter anything that size. As far as cylinder dusting it would take quite a long time even if the filter was allowing very fine dust through. I've rebuilt dozer engines that were run with an air leak on the intake tube for a long period of time. And even then there was very little scoring and only slight dusting. One of the things that contributes to cylinder wall scoring is failure to warm an engine before haulin' @$$. This causes the piston to heat and expand before the cylinder does, causing possible piston skirt to cylinder wall contact........ I think:rolleyes:

[trx400ex]

Well ive talked to these people and they do know what there talking about. They build engines. I would like to know the exact quote he said, maybe he was just trying to simplify it for you. And yes even though i run one i think KNs are inferior to foam on off road stuff like this, just my opinion though. And if anyone doesnt think that dust and small sand particles will hurt your engine do me a favor and take off your carb, lay some dirt and sand inside the intake, now bolt the carb back on and go for a nice long ride..

[markschevy]

he just said over a period of time the engines with k@n filters have had more engine wear over a period of time he said the guys that run uni have had better cylinder wall results he said the k@n flows better and lets more particles into the engines that mx. He said it was not that bad just the uni cylinder walls were easier to clean up.I drag race a 67 camaro and understand this stuff fairly well thats why i decided to post what he said i thought it was interesting.

[Chanman420q]

it doesnt matter what filter you have... if you dont want ur engine to be ***ed you gotta take care of it. SIMPLE AS THAT

[redrider ex]

all i know is i just put a 440 kit in my 99 400ex and it has had the same k&n filter on it when it was new and the cylinder still looked good when i took it apart.

[TORO1968]

Trx400ex, please show me how particles the size of a typical grain of sand (approx. 0.25 mm for medium sand) can get through a K&N filter. I would really like to know...

Besides speculating that a K&N filter lets more dust/dirt/sand through than an aftermarket foam filter does, why don't you disbelievers run some tests in a controlled laboratory setting where operating conditions can be consistently duplicated? Your claims mean nothing unless the performance of each filter is evaluated in comparable conditions.

You don't see magazines like ATV Sport or Dirtwheels test one aftermarket exhaust system at Glamis then go out and test a competitor's product in Denver and compare the results... It makes no sense, and is not fair to claim that one product is better than the other in this case.

It is very difficult to compare these filters by just examining their designs alone. First off, the K&N is a pleated design, relying on large amounts of surface area to filter the incoming air, however, the UNI is a thick foam design, relying on the entire thickness of the foam besides just its outer surface area to filter the incoming air.

These design differences call for the examination of some performance data... Let's see what I can find.

Ah, here we go. This is verbatim from the K&N website, "Air filters are not rated by micron size on an absolute basis. (See technical service bulletin 89-5R from the Filter Manufacturer's Council) The proper rating system for air filters is a testing procedure developed to measure the efficiency of the filtration media at varying micron sizes. We routinely subject a sample of our air filters to this testing procedure conducted by independent laboratories. The primary purpose of this testing is to ensure that our air filter designs meet or exceed automotive industry standards. These filtration tests are performed in accordance with the Society of Automotive Engineer's (SAE) J726 testing procedure. The content of the test dust used in accordance with the testing procedure follows:

Particle Size in Microns---------% by Volume (+/- 3%)
<5.5--------------------------------------13
5.5 to 11---------------------------------11
11 to 22----------------------------------13
22 to 44----------------------------------19
44 to 88----------------------------------28
88 to 176--------------------------------16

Our testing has demonstrated that on average, K&N air filters have an overall efficiency rating of between 97 and 99%. With proper cleaning K&N air filters will protect your engine for the life of your vehicle."

Also from the K&N website, "We design our air filters to provide superior filtration of the contaminants that can harm your engine while maximizing the airflow characteristics of the filter in question. The ability of an air filter to protect your engine is generally measured using a testing procedure developed by the Society of Automotive Engineers identified as the SAE J726 procedure. We subject a sample of our filter designs to this test procedure using Coarse Test Dust, which includes particles ranging in size from less than 5.5 microns to 176 microns. As a point of reference, a human hair is approximately 50 microns in diameter. The result of the above test procedure is a specific air filtration efficiency number. This efficiency number represents the percentage of test dust retained by the filter and thereby kept out of an engine. Our goal is to design our air filters to achieve maximum airflow while targeting overall filtration efficiency at 98%. "

Being a member of the Society of Automotive Engineers myself, I can attest that their tests are comprehensive and impartial when conducted properly.

Another quote from K&N, "There are few areas more confusing than identifying dirt retention requirements when it comes to air filters. Most vehicle owner’s manuals remain silent on the point. In fact, few air filter manufacturers publish any information as to the filtration efficiency of their filters. This stands in marked contrast to oil and fuel filters where there is a relatively large amount of information regarding filtration requirements and capabilities. Studies have shown most engine wear is caused by particles 10 to 20 microns in size. K&N air filters, like most quality disposable air filters, provide excellent filtration of these particles."

Hmm... I browse the UNI Filter website to find performance figures, and much to my surprise, none are provided to the customer... However, they do make this claim below that is not even supported by the ever important test data.

Per the UNI Filter website, "Pleated Gauze or Fabric Filtration - This is another screen type that is only 1mm thick. If the dirt is not stopped on the surface, it is not stopped at all. These filters are sold on the pretense that they maintain an oil curtain for the air to pass through, thereby catching all dirt particles. It is impossible to maintain an oil curtain. The oil soaks the threads of the gauze or cloth, but does not span the openings; otherwise, the air could not get through. The dirt particles that do hit the threads have a good chance of being caught; the others simply go through. The reason the filter does not look dirty on the inside is because the dirt went into the engine. You can easily demonstrate this fact yourself by coating the inside of your housing or carb throat with a thin layer of grease to trap some of the dirt not caught by the filter or you can place a foam filter inside the gauze element to prove the same thing. The one advantage that this type of element has over paper is greatly reduced airflow restriction; however, poor filtration efficiency is the price you pay. When dirt builds up, filtering action improves, but now the airflow is poor like paper elements."

Also, if K&N filters have been linked to noticable engine wear, don't you think that K&N would have gone out of business long ago or at least changed their filter designs?

I don't endorse one product as being better than the other. In fact, I may buy a UNI filter for my 400ex rather than a K&N, however, I do my research before passing judgement on a product.

For more exciting reading, check these links out...

http://www.knfilters.com/facts.htm#FACTS

http://www.knfilters.com/faq.htm#10

http://www.unifilter.com/performance-facts.htm

If a company is confident that their product is better than another, they shouldn't hesitate to post performance figures on their website and list it in their product literature. It could be that K&N is full of it in regards to their products, but if they are willing to post this information publicly, I would believe that the majority of it is true.

Maybe I'll give UNI a call and ask them to provide some performance figures... Let's see what they have to say on this subject.

People, do your research...I'm doing mine! :D

-Jordan

[redrider ex]

Im not saying one is better than the other but if cleaned and oiled regularly they will both do a good job

[TORO1968]

Man, is that a record for the world's longest post, or what? :D

[markschevy]

ttt lets keep this going i knew it was gonan cause a heated debate

[phatswinn]

i read toros whole post lol

i agree with him 100% exept ill write my shorter version of my experiances, i have used a uni airfilter and k&n and stock, i have actually found that foam filters leave more dust in the intake boot and greatly hinder performance one the dust gets caked on the outside of the filter and soaks up the oil, i also dislike the idea of a duel stage foam filter because holes form in the foam that u really have to search for to find, with the k&n i know when its dirty and i can find a hole that could possibly form ni the gauze because it is one layer, so all in a nut shell foam may filter better than a cloth filter, but the cloth filter does a good enough job and increases performance so its good enough for me

the K&N gets my chinese approval-->:chinese:

note: the chinese approval is a regestered trade mark of matt

[TORO1968]

Interesting website... This guy ran the SAE J276 test between a stock paper, multistage foam (similar to UNI design), and a K&N filter for Ducati's.

http://ducatigarage.netfirms.com/filtertest.html

This is the kind of data I've been looking for! Some interesting facts I gathered from this site:

Dirt holding capability (how much the filter can collect before becoming clogged) from worst to best: paper, K&N, multi-stage foam.

Airflow ability from worst to best: paper, multi-stage foam, K&N

The one thing this website does not mention is if any dirt got past the filters being tested... I imagine that if some did, the author would have made a point to mention that to the reader.

Hmmm...time for more research! :D :eek: Actually, time for bed! :huh

-Jordan

[TORO1968]

Sweetness...an entire website dedicated to the ever important test dust used in the SAE J276 test!!!

http://www.powdertechnologyinc.com/new_page_7.htm

Sorry guys, I just had to post it. Its a good read, honest!! :D :huh

-Jordan

[mental1]

Maybe this "scortching" he was talking about is related to people who do not jet properly for the increase in air flow and let their motors way to lean. Maybe but I really don't know what I'm talking about since I don't know the exact affects of running to lean.

[400exredrider]

about using chain lube.......yeah that will work to.....almost any oil will work as long as its not real gritty.......you know what i mean:D

[trx400ex]

Ok, a normal sized grain of sand cant get through a filter in good condition. But alot of smaller particles that could might add the damge up after awhile. But really i could care less, its just an airfilter and every filter out there works better than no filter. Its not like im going to be running the same engine parts for 10 years.

[TORO1968]

Agreed. :)

[Steve-o 400EX]

Originally posted by trailburner
All I can say is what I've seen..I run a K&N [oiled properly] with a outerwear, And I've rode for hours when the dust was so bad I could hardly see the trail, took the filter off to clean it & the inside of the intake boot was SPOTLESS!!!works for me.......

Yes, but the k&N is also very high flow so the motor could be seeing more air than it needs too.