1. After 20+ years it's time to pass the torch. If you are interested in acquiring this forum please contact support@cv-performance.com for details. Any spam will be reported and blocked.
  2. Welcome to Bike Talk, a forum for all bikers and motorcycle enthusiasts. If you are new to Bike Talk, be sure to register for free and join the conversation.

    There's always someone around willing to help out with questions or give a friendly wave back. All Harley and metric riders are welcome.
Bike Talk Motorcycle Forum is For Sale Welcome to Bike Talk

Drlling Vacuum port

Discussion in 'CVP Stage 1 Tuners Kit' started by FATBOY_BO, Jan 3, 2011.

  1. FATBOY_BO

    FATBOY_BO New Member

    Joined:
    Jan 3, 2011
    Messages:
    11
    Likes Received:
    0
    Location:
    Ft. Worth, TX
    I'm getting ready to order a Stage I kit, but another web site, that gives instructions on modifying a CV carb., said to drill the vacuum port to 1/8" dia. Does anyone know what benefit this would add? Do I still need to do this w/ the stage I kit?

    Also, my carb has been modified for my pipes and air filter by the previous owner. The carb has had the plastic fitting changed to the brass fitting, the mixture screw cap has been drilled out. I have not opened the carb. yet. Is there anyway to tell if this carb. already has the stage I kit? If it does, then there is no need to order a new one.

    Oh yea, my bike is a 03 Fatboy, w/ V&H staggers and the stage I airfilter.

    Thanks
    Last edited: Jan 3, 2011
    FATBOY_BO, Jan 3, 2011
    #1
  3. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    do NOT drill the slide!!!!!!! it will cause adverse problems!!!! im not sure which site told you this. i would not use any info from said site.
    how was the carb. modified?? did the previous owner say what was done to it besides "being tuned for the bike".....???
    chucktx, Jan 3, 2011
    #2
  4. FATBOY_BO

    FATBOY_BO New Member

    Joined:
    Jan 3, 2011
    Messages:
    11
    Likes Received:
    0
    Location:
    Ft. Worth, TX
    Thanks for the reply. See below link for the carb mod. that says to drill vacuum port.
    As far as info, the original owner did not specify. I finally got the order in for the CV Stage I Deluxe kit. Can't wait to install it. The reason I am wanting to modify the carb is that my gas mileage does not seem to be very good and motor does not seem very peppy. I get around 35 to 38 MPG at 65 MPH. Maybe that's good, but I have friends on baggers that get better milage. Also, my son's 04 Softail Customs seems like it has alot more getup to it.


    CV Carburetor Modifications
    FATBOY_BO, Jan 3, 2011
    #3
  5. kenfuzed

    kenfuzed Administrator Staff Member

    Joined:
    Jan 1, 2005
    Messages:
    10,513
    Likes Received:
    140
    Location:
    Las Vegas NV
    Chuck is right, avoid drilling the slide with a 1/8" or larger bit. That info was widely accepted many years ago before anyone spoke up that drilling the slide port that large results in the slide bouncing and searching.

    Sometimes all it takes is one site to make a statement and not update the info later to begin spreading like a plague. Last time I checked some of the sites still posting that info hadn't been updated for 10 years.
    kenfuzed, Jan 3, 2011
    #4
  6. chucktx

    chucktx Moderator Staff Member

    Joined:
    Jul 5, 2005
    Messages:
    12,545
    Likes Received:
    10
    thanks for the link. there is some useful info on that site, but there is also some outdated info there too. try to do some research before doing mods. that "performance" sites offer. welcome to the forum........have fun!!
    chucktx, Jan 4, 2011
    #5
  7. FATBOY_BO

    FATBOY_BO New Member

    Joined:
    Jan 3, 2011
    Messages:
    11
    Likes Received:
    0
    Location:
    Ft. Worth, TX
    Thanks for the advice. I was sure not wanting to drill the slide!!!!
    FATBOY_BO, Jan 4, 2011
    #6
  8. fxdxriderleo

    fxdxriderleo Active Member

    Joined:
    Sep 16, 2007
    Messages:
    291
    Likes Received:
    0
    Location:
    Earlville, NY
    If you get Kenfuzed's kit it comes with a drill bit for pulling the idle mix plug. It also is used for drilling the hole in the slide. It doesn't really drill out the hole but removes any burrs or other defects from the factory.
    When I did mine it removed a bit of the color on each end of the hole. It didn't enlarge the hole just cleaned up the ends.
    This and using the spring provided in the kit, greatly improved the throttle responce. No more off idle flat spots. No midrange hesitation. I did the jetting changes first. Much better. I then did the drilling and spring. Great, runs stronger and smoother from idle to redline.
    Last edited: Jan 4, 2011
    fxdxriderleo, Jan 4, 2011
    #7
  9. Tomflhrci98

    Tomflhrci98 Active Member

    Joined:
    Aug 18, 2004
    Messages:
    1,169
    Likes Received:
    17
    Location:
    So. Cal.
    FB, go to this site for better info. This site helped me out a lot when I was learning about the CV carb and how to tune it.

    CV Performance


    .
    Tomflhrci98, Jan 4, 2011
    #8
  10. HarleysLR

    HarleysLR Active Member

    Joined:
    Jun 14, 2007
    Messages:
    2,113
    Likes Received:
    13
    Location:
    Colorado Springs, CO
    the site you listed does have some good info but some is also out dated, I've used that site for well over 10 years and not much has changed, The Delux kit you are getting from CV Performance will wake your carb right up, just follow instructions and don't make it to rich,
    this forum rocks
    HarleysLR, Jan 4, 2011
    #9

Share This Page

XenPorta © Jason Axelrod from 8WAYRUN.COM