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don't shoot me but i have another jetting question. I am going from a uni filter to a k&n filter pro design kit do i need to rejet? i have already rejetted for an open air box lid just wondering if the k&n will let more air in than the uni foam filter to where i would have to rejet? thanks
 

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The k&n should add a little more air but not enough to rejet, unless your already running a little lean.
 

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Originally posted by UFOmile450r@Aug 23 2004, 03:18 PM
The k&n should add a little more air but not enough to rejet, unless your already running a little lean.
agree.
 

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Originally posted by 04450r@Aug 23 2004, 02:08 PM
don't shoot me but i have another jetting question.  I am going from a uni filter to a k&n filter pro design kit do i need to rejet?  i have already rejetted for an open air box lid just wondering if the k&n will let more air in than the uni foam filter to where i would have to rejet?  thanks
this is always a debate.....I personally think the foam filters flow more then K&N. Also I asked a guy who dyno'ed my brothers z400 if he sees better results with a K&N, or with a foam filter. He said he sees way more gains with the foam filters, then with the K&N filters.

To second this theory, I replaced my UNI filter with a K&N with Prefilter, on my sons old blaster and I had to rejet. It was running way rich when adding the K&N. that tells me it was getting more air with the foam filter....but you will get many different oppinions here....You may be lucky and not have to rejet. four strokes arent as picky as 2 strokes. ...hope this helps in your decision. later. B)
 

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you might a point there lude. Ive always like k&n but im not completly sure if it does flow more air than a foam filter. The only way to find out is to try it for yourself i guess.
 

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the k&n does flow more air. it also flows a LOT more dirt. ever wonder why when factory teams can use any filter they choose, they never ever use k&n? here's the acid test: hold up the k&n and look through it towards the light. see all those large holes? so does the dirt! anyone who runs a k&n and has some time on it should remove it and wipe a lightly oiled white paper towel inside the airboot, if you love your motor this experiment will make you ill! this is why there are so many pre-filters available for k&n setups but then you loose the k&n's main advantage; high surface area...............buy a uni..........live long and filter .....mixxer
 

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i agree with mixxer on my 250r i swiched from a k&n to uni because the k&n was letting to much dirt mainly the real fine silt type that is common at most race tracks. the uni was a whole lot better and had to rering my 250r a lot less the rest of the race season
 
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