Jetting Specifications for a Modified Kawasaki KX65

The Kawasaki KX65 is a relatively small dirt bike that is a popular choice for young motocross enthusiasts. The KX65 features a two-stroke engine and Mikuni VM24SS carburetor. Jetting a motorcycle involves changing the amount of fuel in the fuel/air mixture. This is usually achieved by adjusting the jets in the carburetor. Jets are small openings that allow fuel into the manifold. A motorcycle that runs "lean" is one that has a low fuel-to-air ratio while a "rich" motorcycle has a high fuel-to-air ratio.

  1. Needle

    • The jetting needle on a Kawasaki KX65 is a 5gsp68. The jetting needle in the carburetor has grooves that allow it to be raised or lowered, thereby increasing (raising) or decreasing (lowering) the amount of fuel released into the manifold. Kawasaki has used the 5gsp68 needle in all KX65 models manufactured between 2002 and 2010.

    Air Screw

    • The factory setting of the air screw on a KX65 is at 1.5 turns. Turning it in allows more air into the air/fuel mixture and makes the engine run lean. Turning it out has the opposite effect.

    Needle Clip

    • The factory setting for the needle clip on a KX65 is the center position. Turning the clip up makes the engine run lean; turning it lower makes the engine run rich.

    Main Jet

    • The main jet on a KX65 is listed as "190." The number on the jet indicates the rate of fuel flow. As the part number of the jet rises, more fuel is introduced into the engine and it runs more rich (i.e., receives more fuel into the manifold). An engine using a 200 main jet, for example, runs more rich than an engine using a 190 main jet.