Pre-filter

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by sstewart, Apr 11, 2010.

  1. sstewart

    sstewart Long timer

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    If I run a pre-filter on my 950ADV will I have to re-jet carbs?
    #1
  2. Qwik

    Qwik Adrenaline Addict

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    I didnt and the bike runs great. They are a bit lean from the factory and the prefilter will fatten them up too.
    #2
  3. Head2Wind

    Head2Wind MotorcycleMayhem

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    I would say that yes, it will run without changing the jetting. and it also falls into the "it depends" bin... in that if you are at sea level then it will run OK on the bottom, might surge a little in the middle but it will tend to be overly rich at the top... if you are beyond sea level, then it just gets worse.

    So, no you do not have to rejet to run a prefilter, however it will run better if you do.
    #3
  4. Questor

    Questor More Undestructable

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    What about using a pre-filter in very rainy conditions?

    I know the original snorkel was curved backwards so it was difficult for water coming from the front of the bike to get into the air box.
    Should I be concerned with using the pre-filter when riding in very heavy rain at highway speeds?

    Q~
    #4
  5. Head2Wind

    Head2Wind MotorcycleMayhem

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    I live and ride in all conditions in Washington State.... most know what we are famous for (hint, its wet and falls from the sky rather frequently). I have over 12k miles on my prefilter and it has absolutely been flawless in all conditions from 100+ desert to 20 degrees to 40 and raining buckets... even in river crossings it has been just fine. I "tested" its ability to reject water after.. um.. testing the depth of the water with the bike (falling over)... after clearing the engine all was just ducky... not a problem.
    #5
  6. jsrider

    jsrider Long timer

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    H2W won't say it, so I will: If you combine a pre-filter with one of his jet kits, you will be very happy. :D
    #6
  7. mookymoo

    mookymoo Mookish Mook

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    Agreed. I would definitely rejet.
    Even with the re-jet I still found my mains a bit rich.
    I also found that the preflter blocks up pretty quickly. Even riding on the road in non-dusty conditions, I would clean & replace it pretty regularly...
    #7
  8. a$$hole

    a$$hole Long timer

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    Slight hijack here. So on my 990 it pops ALOT of decel and between shifts. I have a 2 into 1 with a very free flowing pipe. If I were to put a prefilter on would it tame some of the farting? Once again sorry about the hijack.:D
    #8
  9. David37

    David37 Been here awhile

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    You won't have to rejet with a pre-filter. I put one on my 950SE and it runs great with the stock jetting.

    If your bike pops on decel, sounds like you have a lean condition. I would try turning out your air/fuel screws 1/4 to 3/4 turns to richen your air/fuel mixture. An exhaust leak can create a lean mixture too.
    #9
  10. Oldfatbeerman

    Oldfatbeerman Enroute to a PUB

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    Uni filter pre filter is plug and play :1drink .
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    #10
  11. mookymoo

    mookymoo Mookish Mook

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    :scratch .... that tends to go against the grain of the general consensus here as I understand it....

    As H2W mentions above, mains will be rich even at sea level...

    Its a reasonable restriction on the intake (worse, if its heavily oiled, and worse again when it gets dirty) ...
    #11
  12. ryanwilliamcantrell

    ryanwilliamcantrell Get Out and Ride!!

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    Having put 10k on a new pre-filter last year, I HIGHLY recommend it. It's saved me from having to mess with my filter constantly. As someone else said, it'll plug with dirt quickly and frequently (which means its doing it's job) so keep an eye on in.
    #12
  13. Oldfatbeerman

    Oldfatbeerman Enroute to a PUB

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    I was assuming the jetting had been set correctly before the filter was installed ........ mine had and I fitted the pre filter and there is no ill effect , runs just fine , has same economy ( provided pre filter is clean ) feels to have the same output , power and torque wise . Still needs same amount of Choke to cold start in summer ( lots ).... I have not done anything scientifically significant to tell all that for sure though . Seat of the pants works for me !

    Some of the gentlemen here are a bit over the top with the state of tune they demand on 100 hp dirt dikes . You can't use all that power on anything but Tarmac so a small amount of richness in the running will have your bike running cooler and will probably last a bit longer because of it . Swings and roundabouts :wink:.
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    #13
  14. Geek

    Geek oot & aboot

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    Does anyone have a uni part number or a link to the prefilter online?

    Mine has a hole in it :patch
    #14
  15. dad2bike

    dad2bike Retired! Cranky Old Fart

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    #15
  16. zenKTM

    zenKTM -

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    my stock SE ran ratshit when i put a prefilter on,what H2W describes x3:

    i was getting ~250km to a 30L tank :deal

    with the H2W kit I get 350km to a tank, still ratshit mileage but the bike runs great :D
    #16
  17. y0y02369

    y0y02369 Long timer

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    sorry for arriving super late to the party fellas!

    I was wondering what a pre-filter is what the advantage is of installing one? I had a KLR and went everywhere with and never even heard of a pre-filter... pardon my lack of knowledge! Just trying to learn more! :lol3:lol3
    #17