runnin too lean

Discussion in 'Engine, Fuel and Exhaust' started by cdomatt, Aug 3, 2014.

  1. cdomatt

    cdomatt New Member

    how would I determine the right size of jets for a Keihin CV carb. its running really lean.... it was a 1999 - 883 when I bought it, and has undergone some changes since then. put a big bore 1200 kit and set of buell lightning heads...
    Radii Curved Exhaust Headers. any ideas??? I appreciate any info.... help.
  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    Welcome to the forum
    A 180 or 185 for the main jet and 45 or 46 for the slow but as the carb is a few years old may be a good idea also to do a full rebuild using a rebuild kit to replace all the rubber parts

  3. Dr. Dolittle

    Dr. Dolittle Experienced Member Contributor Retired Moderators

    I moved your thread into this section to get more responses - please feel free to go back to the New Member section and post an introduction!
  4. 03HD883R

    03HD883R Active Member

    I recommend 45 pilot 180 main, and about 2.5 to 3 turns on the mixture screw. It also helps if you get a EZ-JUST mixture screw, you can make adjustments using your fingers instead of fumbling with screwdrivers. Make sure you are doing it around the 900 rpm range.

    One key indication of too lean is popping thru the air cleaner when suddenly opening the throttle or going down hill and it's popping away like popcorn in the microwave.

    One key indication of too rich is poor sudden acceleration, such as hesitation.

    If you need to do more 4 turns of the mixture screw it is highly advised to go to the next size jet, which would be a 48 pilot.

    Also, it's never advised to go too rich because of cylinder wash down and carbon buildup. Not to mention it will make your bike REEK when running!

    I've got a plain-Jane 883R pretty much stock except for the rejetting wiith a NOKH needle and EZ-JUST mixture and idle screws, got a 2ki ignition module, and a Voodoo 3 ohm DF coil with SE FAT wires. Right now I've got it set with a 45 pilot, stock 160 main, with 2.25 turns on the mixture screw. Runs like a charm.
  5. Jack Klarich

    Jack Klarich Guest

  6. Jack Klarich

    Jack Klarich Guest

    Here is your idle adjustment screw
    If it has not been adjusted yet, you will have to remove the welsh plug that covers it, simple, drill a i/8th inch hole in it insert a self tapping screw grab it with a pliers and pop it out:s
    Welcome to The forum
  7. 03HD883R

    03HD883R Active Member

    Great advice Jack. Also, it helps to wrap the tip of the drill bit about 3/16" from the tip. If pliers don't want to work, use a screw... I used a coarse thread sheet rock screw to give it good bite. It should just pull right on out.

    As for figuring out where your stock setting is, I always mark the screw with a pencil and then turn it until it's lightly seated counting the revolutions then write it down.

    If you mess up and wind up drilling too far, it will turn the mixture screw, so you have to guesstimate, or just do 2.5 turns out and start fine tuning from there.

    You'll know where your bike likes it... it may take a few attempts, but you'll know by the seat of your pants and what you hear. That's what I love about the EZ-JUST screw... I've played with it at intersections and long traffic lights to get mine just right.