air filter

[TRAV05]

i have a stock air filter and wanting to remove my air box lid for more performance, will it make a difference using my stock air filter, i will be upgrading shorty to eithier a kn or an uni but until then. and what do i use as my rejet and how do i do that
also cleaning my stock filter what to use
thanks

[rooster300ex]

To me the best thing to do is get one of those power packages. It comes with a dynojet jet kit W/instructions,k&n filter & recharger kit, and an outerwear to help keep it cleaner with no airbox lid.Sweet Quads (http://www.sweetquads.com/index.php?action=item&id=64&prevaction=category&previd=16&prevstart=0)

[ohsobad_chevy]

Holy chit, 115 bucks for a k&n, jet kit, and outerwear. Someone is getting ripped off big time. Dude, buy a uni filter for 30 bucks, take off your air box lid and buy a new pilot and main jet for about 10 bucks. My personal opinion: k&n's are junk on a quad. I have seen too much dirt and sand get past em, even with the outer wears on. Don't start bashing me now because I said I don't like K&N's, I just stated my opinion from my personal observations. ;)

[400exstud]

Don't buy a jet kit. If you are getting into tweeking quads you must teach yourself how to jet it. In the long run you will be much happier and more knowledgable.

I have a K&N and don't have a problem with it. Just keep it oiled.

[rooster300ex]

Don't listen to nothing they said. You save like 30 bucks buying a package then buying each part.k&n is the best.

[400exstud]

Originally posted by rooster300ex
Don't listen to nothing they said. You save like 30 bucks buying a package then buying each part.k&n is the best.

There is no doubt that you will spend more, but the education about tuning your bike is well worth it.

I am 16, and a year ago I tought myself how to properly jet an engine. My dad was so afraid of carbs that he wanted nothing to do with it. Now that he trusts me, he will help me along when it needs a change.

[TRAV05]

i am picking up a twin air air filter today, what are ur thoughts

[ohsobad_chevy]

twin air is good as well. They all will do there job with proper maintenence, you can get a little longer use time out of a UNI or twin filter, compared to a k&n. K&N's are good as well, just take more maintenence as far as keepin them clean and oiled.

[04TRX400EX]

If you are looking for some more performance, you should really replace the stock filter in addition to taking off the lid. With no lid, you definitely need to rejet the main on the carb and possibly the pilot. From experience in talking to several people about jetting though, you usually don't have to mess with the pilot jet unless you are building-up the engine (bore, cam, etc.). In your situation, as is mine, you probably will need to change the main and then move the clip position down on the needle. You may also need to adjust the air/fuel mixture screw. I recently taught myself how to do this and I now feel so much more comfortable with jetting ... the dreaded subject isn't that bad actually :) Check out the "How To" section on here and read the 3 or 4 threads about jetting a 400EX and you should be set.

BTW, I run a K&N with Outerwears and have had no problems thus far. I like it especially because they're easy to clean. That being said, I don't have experience with UNI's, do IDK.

[ohsobad_chevy]

[i]BTW, I run a K&N with Outerwears and have had no problems thus far. I like it especially because they're easy to clean. That being said, I don't have experience with UNI's, do IDK. [/B]

I have seen many cylinders off of 'shees, blasters, 250rs, lts, you name it, they all were running a k&n air filter and their cylinders looked horrible. Then again, they probably did not keep it clean and oiled properly either. I just have always been a UNI man, myself. Don't get me wrong, I am sure that k&n's work great, but I am just going off my person observations as stated above.

[TRAV05]

i am running a twin air filter and no lid, how would i go about jetting my jets to i need to buy news one or can i adjust the ones in it

[exrider008]

i have a k&n and filter with an outware and i am getting a UNI cuz the k&n lets A TON of dirt through and i clean/oil it every time i ride!

[rooster300ex]

Originally posted by exrider008
i have a k&n and filter with an outware and i am getting a UNI cuz the k&n lets A TON of dirt through and i clean/oil it every time i ride!


no offense but thats a bunch of you know what. k&n is the best filter money can buy. everytime i've taken my filter off to clean it i've never seen a spec of dust on the carb boot or anywhere,execpt for the outside of the fliter. the inside of my k&n still looks new. you gotta oil them right.

[ohsobad_chevy]

Originally posted by rooster300ex
no offense but thats a bunch of you know what. k&n is the best filter money can buy. everytime i've taken my filter off to clean it i've never seen a spec of dust on the carb boot or anywhere,execpt for the outside of the fliter. the inside of my k&n still looks new. you gotta oil them right.

How many cylinders have you seen that have been ran off a k&n. I'll sure tell you that 98% of them will look like chit, like I stated, they all work and do their job, but the k&n takes more maintenence than most folks are willing to give it. I am simply stating: K&N's take more maintenence than a UNI or a twin to do their job effeciently. I seen approximately 50-60 cylinders of people that have ran K&N's and their cylinders looked horrible(probably cause they didn't keep em clean) and I have seen just as many cylinders that were using a UNI filter, and they looked 110% better. K&N's flow a little too well, requiring them to be constantly cleaned and oiled generously.

[exrider008]

Originally posted by ohsobad_chevy
How many cylinders have you seen that have been ran off a k&n. I'll sure tell you that 98% of them will look like chit, like I stated, they all work and do their job, but the k&n takes more maintenence than most folks are willing to give it. I am simply stating: K&N's take more maintenence than a UNI or a twin to do their job effeciently. I seen approximately 50-60 cylinders of people that have ran K&N's and their cylinders looked horrible(probably cause they didn't keep em clean) and I have seen just as many cylinders that were using a UNI filter, and they looked 110% better. K&N's flow a little too well, requiring them to be constantly cleaned and oiled generously.

thank you. i just got done rebuilding/boring my 2002 400ex because i sucked in dirt threw my k&n filter. and just so u know i do oil it right.

[spent21]

if you guys go to NACS Racing website (or have a catalog), they have a chart that shows you throttle position and what carb adjustments will effect those positions, ie. the air screw is from idle to 1/3 throttle, main is from 2/3 to WOT etc. it is really a useful piece of information to have at a glance.

i looked for that chart, but i can't find it. however, i did find this:

http://4strokes.com/tech/honda/carbadj.asp

this has been bothering me, so i found a better site that i had forgotten about. all you need to know!!

http://www.keihin-us.com/am/_media/pdf/slide_valve.pdf


good luck