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Dirty Harry.... Moderator
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Discussion Starter #1
I need a second opinion from all you guys/gals that have a K&N filter installed in your ZR(s). I installed the K&N filter about 6 months ago. Recently, the dealership that I bought my bike from was sold to a Honda/Suzuki/Triumph dealership. My friend and now "former" mechanic at the old Kaw dealership has advised me to "chunk" the K&N filter in favor of the stock filter. In his years of experience, he says the K&N just allows to much crap into the carbs, and says he has had to rebuild an engine (on a cage) because of the crap the K&N allowed into the engine. He is going to rejet my bike soon, and tells me that with the Yosh pipe I have and rejet (and carb synch) I'll be good to go. But trash the K&N filter. Any thoughts on this? I appreciate it. Tom :?
 

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Tom! What the heck are you trying to do? Open a mega can of Worms with this K&N question? This debate has been going on for as long as there has been K&N filters. If fact, depending on who you talk to, there is enough evidence to support both arguments. I have talked with people who swear by them and other people who would not put one on a borrowed lawn mower. You are going to get flooded with opinions--both pro and con--so I might as well get mine in first!

If properly maintained, I believe K&N filters provide sufficient filtering. In fact, I have been using them since 1977 without any problems. Here is what I tell people who ask the question you have asked. The performance gain by using a K&N filter (relative to other modifications) is marginal; so if you are in fact worried about the potential harmfull affects of using this type of filter, then don't us it. With respect to using one in the ZR-7, the airbox itself is so restrictive, the type of filter you put inside of it does not make that much difference. Now if you have modified the airbox to flow more air, then the selection of the proper filtering element can make a difference. Your mechanic friend has experience that tells him that K&N filters are junk. You could easily find another mechanic that will tell you just the opposite.

So here is the bottom line. You are not going to get a quantifiable answer to your question--you are only going to get opinions. And I am willing to bet, you will get more opinions in favor of K&N filters than against. But just remember one thing, no matter the result of your inquiry, your mechanic friends' opinion will not change.
 

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MotoMacGyver
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Tom (either one :laugh: ),

I agree. Almost every race car engine I've ever seen runs a K&N filter. But.... those engines also get rebuilt every few races. And the performance gains are marginal as Tom D. said. Fact is, a cleaned and oiled K&N will do a fine job of filtering. But, it gets clogged just like an ordinary filter as grit/debris/whatever builds up in the oil suspension, thereby negating your performance advantage.

If you keep it clean and oiled, it will flow noticable better (maybe not seat of the pants, but I'm talking flow numbers on a flowbench) than a stock paper filter. Now, that doesn't mean it FILTERS better than a stock filter. K&N's (contrary to popular belief) are not foam filters; they are made of paper as well. The "spacing", if you want to call it that, in the paper mesh is bigger than a stock filter, thereby getting you better flow. However, this flow is really noticed at higher engine speeds (intake charge speeds).

My belief is this: Yes, it does flow better, and yes you'll gain some improvements if you match your fuel, exhaust, etc. I do NOT think it filters better than a stock filter. However, I also believe that the fine particles it may allow to pass through do not harm an engine that is otherwise taken care of. Your engine oil will do much more "filtering" than you think. Neither filter (unless it's damaged or something) will let in particles big enough to do any serious damage to cylinder walls or anything.

It's like everything else in life, a compromise. Better flow but not as good filtering. But the filtering it does do, is still sufficient for an engine.

My opinion.

Emrah
 

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West Coast Moderator
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I'm gonna disagree with you on the "fine particles" not hurting the motor Emrah. Any amount of particles allowed to get into the motor is going to add to the materials that are already there(clutch dust, old oil, metal dust from normal wear) and make a bad situation worse.
 

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K&N Filters

A K&N Filter came with my Holeshot Jet Kit and I had no question about installing it. It's the first I have heard a bad rep on it. My brother races a V8 Chevy Vega and the filter he uses is K&N. It probably helps not to ride in a real dirty environment like gravel or dirt roads. I f you can keep the ZR7 on pave streets and maintain it regularly I would'nt have a problem with my K&N. The performance gain after the jet kit, silp-on and K&N was a good difference. Kim:cool:
 

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Wheelie for Safety
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1,550 Posts
I find the K&N filters air much better than the visor. However, visibility sucks... :laugh:



Andy
 

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OK.

Here's what the K & N site says about their filtering capablilty.
------------from K&N Q&A section------------
10. What is the micron rating and filtering efficiency of the K&N filter?

K&N air filter designs are tested both in house and by independent testing laboratories for air flow, filtering efficiency and dust retention. The Society of Automotive Engineers (SAE) establishes testing standards for automotive air filters. Independent testing of panel and round K&N air filters has confirmed an overall efficiency rating of over 99% when tested using the SAE J726 air filter test code. The test results provide scientific details including particle size, size distribution, testing methodology and results. The overall results establish the superiority of our filters against the “competition”. The OEM minimum specification is 96% with ISO (International Organization for Standardization) test dust which consists of a majority of 0 to 5 micron particles but some up to 20 microns in size. Test results showed that a paper filter has a 99.29% cumulative efficiency and a 96.47% initial pass. A K&N filter, with far less restriction than paper, has a 99.05% cumulative efficiency and a 97.11% initial pass.
------------------------end--------------------

Not sure what a foam filter rating is.

BTW. the K&N part # is KA-0850.

Bowman
 

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i can't say for sure which is better but i can say this, if you don't keep your k&n filter properly oiled you might as well run no filter at all. the oil applied to the filter is a critical part and it's almost worthless without it.

scott :)
 

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Gold Member/Community Dad
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Tom,

I believe Scott has a very good point! If you neglect to maintain the K&N filter then it would likely pass more particles than a neglected stock paper element. Was trying to find a research article I saw several months back but can't find it - what I do recall about it was the K&N did a great job on the air flow, but left alot of debris through compared to many others! I've used K&N and can say it does breathe better. What we can't deny is K&N has done a pretty good job of marketing.
To further confuse look at this chart about 2/3 of the way down the page. http://www.amsoil.com/products/ts.html

But being "the rebellious one" you are... why are you even asking?

Berto
 

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Dirty Harry.... Moderator
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Discussion Starter #10
Thanks guys, I'm gonna keep the K&N installed as it is and check it regularly. Hey Bowman, just when are you going to insert the "witty quote?" I appreciate the info, I know I've heard it before, just couldn't remember the pros and cons. Tom :D
 

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Dirty Harry.... Moderator
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Discussion Starter #11
Berto said:
Tom,

I believe Scott has a very good point! If you neglect to maintain the K&N filter then it would likely pass more particles than a neglected stock paper element. Was trying to find a research article I saw several months back but can't find it - what I do recall about it was the K&N did a great job on the air flow, but left alot of debris through compared to many others! I've used K&N and can say it does breathe better. What we can't deny is K&N has done a pretty good job of marketing.
To further confuse look at this chart about 2/3 of the way down the page. http://www.amsoil.com/products/ts.html

But being "the rebellious one" you are... why are you even asking?

Berto
Ha Ha, thanks Bert, I'm asking because I am the "rebellious one," you know, the guy that stirs up SH^T everywhere he goes...just kidding, I did want to know, it's my bike man, ain't worried about anything else. Tom :smilewink
 

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i have a k&n filter in my car with over a 100k on it. and i yet had a problem nor anyone i spoke with has heard of this problem on both bikes or cars.
 

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boxsky,
1) what kind of car/engine?
2) how often do you clean and re-oil the filter?
3) how often do they recommend cleaning and oiling the filter?
3) do you drive in dusty conditions?
scott :)
 

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1) 1.6l honda open air filter 107k & 1.6l honda box filter 86k
2) on the 1st one about every 15k & every 30k on 2nd
3) i don't remember what they recommend i think around 15k or 30k, i check the filter at least every 3 to 4 months to see if needed
4) high pollen count during summer and somewhat dusty for north east due to much local constructing
 

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thanks for the info:) it sounds like good anectodal evidence for k&n. another bit is that lots of desert off roaders swear by them. that's as dusty as you can get! many of these are amateurs so they don't necessarily rebuild the engine every time they go out but they may be cleaning and re-oiling their filters more.

scott :)
 

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I know this is just an opinion, but I love the K&N products. I'm not saying they are better or worse than other products, I've just used them in various vehicles over the past 10 years and have never had any trouble. However, You do have to maintain them. Everyone is correct; the oiling process is critical to the performance level of the K&N. I don't think you could go wrong either way. If it bothers you that much, just get a normal filter and don't worry about it.

just my .02

max:)
 

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Dirty Harry.... Moderator
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Discussion Starter #17
Hey Max, I'm keeping the K&N in place. If I hadn't of talked with my mechanic friend Pat, I never would have started this thread to begin with! But it has been very informative -- thanks for the input, Guys. Tom :cool:
 

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The Deer Slayer
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How often do you folks clean and re-oil the K&N in the bike? I've had mine in for one season so far, maybe 5000 miles or so. I haven't been in there to check it since. I figure I'll do a tune up in spring, plugs, filters, lube stuff.

I saw the cleaning, re-oil kit, but haven't bought it yet. Do you spray the element down, then rinse off ? I thought the literature, buried somewhere, had said filter works better after it's been in for a while. Bike really needs a tune-up, must find time.

I'll vote late here, in favor of K&N. It seems a necessary part of the intake, re-jet, exhaust upgrade. Hey its a modification, not stock, but I really don't think...OPINION...OPINION...a well maintained K&N will harm engine any more than stock.

Tony, man of little knowledge and much opinion.
 

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It really depends on the area as to how often you need to clean it (i.e. how dusty it is there); but you can't go wrong if you do it every other oil change (my opinion). It's real easy, you just spray the cleaner on the filter, run water through it (from the inside out) until clean. Let it air dry, then re-oil it. The hardest part is just simply getting it out.
 

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Dirty Harry.... Moderator
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Discussion Starter #20
MedZR7Treker said:
How often do you folks clean and re-oil the K&N in the bike? I've had mine in for one season so far, maybe 5000 miles or so. I haven't been in there to check it since. I figure I'll do a tune up in spring, plugs, filters, lube stuff.

I saw the cleaning, re-oil kit, but haven't bought it yet. Do you spray the element down, then rinse off ? I thought the literature, buried somewhere, had said filter works better after it's been in for a while. Bike really needs a tune-up, must find time.

I'll vote late here, in favor of K&N. It seems a necessary part of the intake, re-jet, exhaust upgrade. Hey its a modification, not stock, but I really don't think...OPINION...OPINION...a well maintained K&N will harm engine any more than stock.

Tony, man of little knowledge and much opinion.
Tony, your'e still "The Man" -- Hey, all you need is an opinion!! Tom :rolleyes:
 
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