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

CV Carb Help

Discussion in 'CV Performance' started by ajaspengren, May 3, 2011.

  1. ajaspengren

    ajaspengren New Member

    Joined:
    May 3, 2011
    Messages:
    2
    Likes Received:
    0
    I have an 89 Ultra Classic with an 80" Evo. I have installed an Andrews EV-27cam, adjustible pushrods, lifters, new coil, electronic ignition, wires, plugs, and SE intake. I have rebuilt the carb and installed the CV Performance tuners kit, EZ-Just idle screw, 190 main jet, and 48 pilot jet. The bike runs great in and around town but acts like it is running out of gas at speeds above 65mph. It dosn't do it all the time, but more often than not.

    Anyone have any ideas before I give up on the stock carb and install the mikuni carb that I have sitting on the shelf?

    Thanks
    ajaspengren, May 3, 2011
    #1
  3. kenfuzed

    kenfuzed Administrator Staff Member

    Joined:
    Jan 1, 2005
    Messages:
    10,512
    Likes Received:
    140
    Location:
    Las Vegas NV
    The main jet seems a bit large (rich) for that size engine. One way to tell is by getting up to speed and hold at full throttle, then let off the throttle by only a fraction (approx 1/8" turn).
    1) If you feel a momentary surge or pulling acceleration as the throttle is slightly let off then the main jet is too lean.
    2) If it feels sluggish, hesitates, or emits any smoke it is too rich.

    The transition from full throttle to 3/4 throttle should be smooth and precise if the main jet is correct.

    Double check for intake leaks (very common) around the intake manifold boot and flanges to the heads. When checking intake leaks check with the aircleaner on as some aftermarket backing plates will pull the carb slightly away from the manifold. Also I didn't see mention of the type of pipes. Open drag pipes will cause flat spots or sluggishness at different spots depending on the particular pipes.
    kenfuzed, May 3, 2011
    #2
  4. ajaspengren

    ajaspengren New Member

    Joined:
    May 3, 2011
    Messages:
    2
    Likes Received:
    0
    I was wrong about the jet sizes. I have a 185 main and 46 pilot installed right now. The bike has stock pipes right now, but I will be putting Reinhart slip-on's eventually.

    I have put about 400 miles on it since my last post. I did the throttle test and it does continue to pull when you let off 1/8 turn after full throttle. Then if I let completely off it seemed to pop after which would indicate lean. The plugs look a little light in color to me. I agree that a 190 main jet may be to big. What is the best way to check for intake leak?

    Thanks

    ajaspengren, May 9, 2011
    #3
  5. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    To check for leaks, use an unlit propane torch. with the bike running and I prefer with it warmed up, open the valve and go around all areas around the intake to heads and I also check around the rocker boxes to see if there are any possible leaks there. Or you could do it the messy way and use WD40
    JohnnyBiker, May 9, 2011
    #4
  6. kenfuzed

    kenfuzed Administrator Staff Member

    Joined:
    Jan 1, 2005
    Messages:
    10,512
    Likes Received:
    140
    Location:
    Las Vegas NV
    Also 2 of the most common points of intake leaks I see on Evo's is either the rubber boot between the carb and manifold or the vacuum hose going to the VOES switch. Also worth noting, you didn't mention what air cleaner you have but using a Hypercharger intake has commonly caused intake leaks when attaching the vacuum line (Tee) into the existing line.
    kenfuzed, May 9, 2011
    #5

Share This Page

XenPorta © Jason Axelrod from 8WAYRUN.COM