The tedious work of changing jets between numerous test laps was well worth the improvement in top end power, low end grunt and smooth throttle response. With our Mikuni dialed in, our engine feels like an entirely different beast. Experiment with different jet sizes until the desired performance is achieved. If there is a part of the power band you would like to tweak a little more, use the tuning manual to determine which jet controls that area of the power band. Take note as to how your engine performs in all areas of the track. Remember to shut the engine down immediately when you pull to a stop, without letting the engine idle, to ensure you get an accurate plug reading.Īfter you find the desired main jet, you can move on to the other carburetor adjustments. Repeat this process until you get a good tannish brown plug reading. Run a few more laps at a racing pace and check the plug again. Start your tuning process by going to a larger main jet. Chances are the plug will be white, indicating a lean condition. Bolt the carburetor up and run it for a couple laps with this setup. Tips: Our 22mm Mikunis come with a 95 or 100 main jet and 15 pilot jet. We recommend reading the tuning manual and trying different setups in order to achieve the biggest horsepower gains from this performance carburetor. If you copy our setup you may or may not see great results. Our testing resulted in this final setup: 130 main jet, 12.5 pilot jet, needle clip in the center position and air screw two turns out (stock position). When we tuned our Mikuni we tried about ten different main jets, five pilot jets and every clip position on the needle jet. Jetting that works great with one engine may not work so well with another.Īrmed with an assortment of jets and a free afternoon, we are confident you can tune your Mikuni for optimum performance. Unfortunately, there isn't a universal setup that will work with every engine combination. There is a large amount of horsepower to be found in a properly tuned carburetor.

Mikuni tuning manual