K&N Air Filter

Discussion in 'Engine, Fuel and Exhaust' started by kerry, Feb 23, 2010.

  1. kerry

    kerry Member

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    I'm kind of new to fuel injection----can I run a K&N air filter on my totally stock Nightster without it making it too lean? Thanks,kerry
     
  2. Chopper

    Chopper Senior Member

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    If you just use a K&N filter in your stock air box you should be ok, but if you change the whole filter assembly to a free breathing one you will need a download, fueler or tuner the add fuel to the mix.
     
  3. glyd-n

    glyd-n Junior Member

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    Chopper has you covered. You're safe with just the filter.
     
  4. murf

    murf Active Member

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    I agree with Chopper but would also suggest some free breathing slip on mufflers to get all that exhaust flowing out after increasing the amount of air flowing in. Would sound better also.
     
  5. Jack Klarich

    Jack Klarich Expert Member

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    Chopper has u covered here, changed mine on my 07 Streetbob with no ill effects, changed the exhaust also no problem here after10,000 miles but if I was to change the entire air box I would for sure add a tuner
     
  6. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    By itself, comparing the K&N to a fresh HD OEM air cleaner element of comparable size may see 10-15% more air flow...perhaps more over the same amount of time as more dirt gets trapped.

    The real key is that when you actually change the aircleaner element AND housing, the larger exposed area to open air, means less restrictive element over area. Heavy breather works by virtue of totally open perimeter, filtering area is a bit smaller regarding filter element area, but certainly more than stock.