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Thread: '08 DX Running Rich

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  1. #1
    lerock Guest

    Cool '08 DX Running Rich

    I have a 2008 VRSCDX, 1250cc, SC air cleaner, air box cover ON, stock computer, & Fat Shots. Up to 11 disks & it seams to still be running rich. Haven't dynoed it, but more disks "appears" to be lowering midrange tourque without improving top end. '08's have the dual ox sensors. Should I keep adding disks till it starts to lean out? Is the computer trying to over compensate?

    Thanks,

    Mike

  2. #2
    Join Date
    Jul 2007
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    8-10 on a stock bike is typically the magic number. How 'rich' is it? smoking? bogging?
    Typically,more discs, you would see a slight drop in bottom end and a slight increase in top, depending on fueling of course.
    It may be throwing more fuel at lower rpm/throttle setting/load making it rich, and not enough at higher rpm?
    Interesting, have not noticed that or heard of it.

  3. #3
    lerock Guest

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    Not somking, but black soot on the exhaust & plugs. Runs fairly strong across the power band, no pops on deceil. Also, has a mid range flat spot or stumble when cold. Have not tried it above 12 disks.

  4. #4
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    Jul 2007
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    Hmmm?
    Hard to say without seeing it. Just for giggles you might try taking all the discs off and running around the block to see what it does?

  5. #5
    lerock Guest

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    Open, no end cap right?. I'll try it this weekend.

    Mike

  6. #6
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    Jul 2007
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    Yes, completely open.
    Ideally, you would do this with new plugs and take a reading (search NGK's website for proper color info).

  7. #7
    lerock Guest

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    Quote Originally Posted by jwells View Post
    Hmmm?
    Hard to say without seeing it. Just for giggles you might try taking all the discs off and running around the block to see what it does?
    Well, it took a bit longer than I thought it would, but here are some results:
    As it turns out, the soot is from the cold start circuit, it just doesn’t seem to go away from the disks.
    The motor was a weak suck with no disks, in fact it was flat until I got down to 11 disks. The plugs looked a little lean, but not scary. Guess the EFI tunability is a bit limited.
    With 10 disks the thing pulls hard, the plugs were a nice light tan, with no pops or pings. Which seems odd, it is your recommendation to run 10 whither we have an 1130 or 1250cc motor. I was running 21 disks on a 95 inch motor with a Super Trapp 2 into 1. 20% more displacement, but with about the same amount of disks. Displacement most not be that big of factor. Maybe it’s the amount of air moved vs. rpm?
    Anyway, thanks for your help. Wish you guys made a black 2 into1 for the Night Rod Special.

  8. #8
    Join Date
    Jul 2007
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    Good to hear, sounds like you on the money-or very close too. Tan is good on the plugs. Ride it and have fun.

    Displacement, HP, type of engine are all factors. Then throw in core design, number of mufflers, cam profile, use of vehicle, sound/emission requirements, etc, then you have a few of the tuning factors.

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