Jet Kits and Airbox Modifications

Discussion in 'General VFR Discussions' started by ChrisPaegelow, Mar 19, 2007.

  1. ChrisPaegelow

    ChrisPaegelow New Member

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    Hey guys I have another question.

    Yeterday when I was messing with my gas tank, I figured I'd take a look and see how the air filter looked. This was the first time checking out the air filter, since I just got the bike last summer, and I didn't put many miles on it. Well, lo and behold, the previous owner (or the dealer I bought it from maybe) put a K&N air filter in there. Ok, so that's pretty cool.

    Anyway, now I just bought a set of Cobra F1 slip ons from ebay, and I'd like to throw them on there in the next couple weeks.

    I've heard that when you mess around with the airflow by using a replacement air filter, or installing fancy new exhausts, you should re-jet the carburetors so they don't run too lean.

    So, I'm guessing I'll need to stick some new jets in there after I install the new mufflers. What do you guys think? Where can I get a decent jet kit? K&N has one on their website for my bike for $35, but I've seen some that cost much more than that.

    Also, what's involved in the whole rejetting process? How do you know if you got it adjusted right?

    And while I'm at it, I have also read that people cut holes in their airboxes and stuff like that to get even more airflow. Does this improve anything, or is it just asking for trouble?

    Thanks everyone!
    -Chris
     
  2. GenLightening

    GenLightening New Member

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    In general, the K&N doesn't flow that much more air to need rejetting, and the slipon exhaust is the same. Now, most bikes come from the factory with lean jetting, so you might go up one size on the mains (get them at any bike shop for a couple of $ each) and check where the PMS is set on all 4. As for the holes in the lid, I did mine, but I've got full exhaust, cams, etc. All it'll do is make more noise.
     
  3. ChrisPaegelow

    ChrisPaegelow New Member

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    Well, I do love noise... How did you do it? I mean, where did you put the holes, how big are they, how many, etc.
     
  4. RVFR

    RVFR Member

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    it's a tuff one to do and on the V4 motor even tougher, really helps to have a dyno close by too. Been thinking of this very thing also, but after talking to the pros, unless I find the HRC kit, I'm not touching her carbs.
     
  5. GenLightening

    GenLightening New Member

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    I used a 1" spade bit on the lid, and without pulling the tank I couldn't tell you how many. Once I get room in my shop I'll be going through it to get it track ready again (a somewhat scary thought!) and I can take some shots of it.
    Another free upgrade is when you pull the carbs, check out the manifold boots to intake sizing. You'll probably notice the inside of the boots are a bit smaller than the carbs and intakes. Find a socket or dowel that fits into the boots, wrap it with sandpaper and sand them so you have a smooth transition from carb to head. It's good for a 1-2%hp increase and free.
     
  6. ChrisPaegelow

    ChrisPaegelow New Member

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    Sounds like a pretty good time.

    I'll see how it works once I get these new pipes on, and then go from there.

    What are the signs that would tell me I'm running too lean, or that some adjustments are needed?
     
  7. tbones86

    tbones86 New Member

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    White spark plug electrode porcelin & "pinging"
     
  8. GenLightening

    GenLightening New Member

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    If while at speed and you crank open the throttle it will die. If you then open the choke slightly and repeat opening the throttle and it responds then you know it was lean. And check the plugs.
     
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