Cars & Vehicles Auto Parts & Maintenance & Repairs

How to Tune Up a 1977 Honda Z50 Carburetor

    Remove the Fuel Line

    • 1). Turn the fuel supply lever to the 'Off' position. This is located near the kick starter.

    • 2). Clamp the fuel line shut two inches from the carburetor connection. Slide the fuel line off the carburetor spout.

    • 3). Unbolt the two bolts that hold the carburetor on the motorcycle using a 3/8 socket.

    • 4). Take off the air cleaner filter assembly. The air cleaner assembly is connected to the carburetor with a thin tube. Remove the clamp from the tube with a pair of pliers. Pull the tube away from the carburetor.

    Inspect the Carburetor

    • 1). Rinse the carburetor with automotive engine solvent. Dry it thoroughly using canned air.

    • 2). Check the float by shaking it. If there is any gasoline in the float, the float must be replaced. Check the float shape. It should be free of dents and bumps. Finding any imperfections means you must replace it.

    • 3). Inspect the bolts and bleed screws. These must be replaced if the bolts or screws are stripped or damaged.

    Adjust the Throttle

    • 1). Turn the throttle stop screw using a flat-head screwdriver to the 1200 RPM mark. This is located on the top side of the carburetor.

    • 2). Adjust the air screw to the highest mark. If this moves the throttle stop screw reading, you must readjust it to the 1200 RPM mark. Continue alternating between the two screws until they are both positioned properly.

    • 3). Replace the main jets. If you noticed the motorcycle was idling too high prior to cleaning the carburetor, you should replace the main jets with the next smallest size. If you noticed the motorcycle was choking out, you should replace the main jets with the next size up. If you replaced the jets with ones of a different size, you must readjust the screws again.

    Replace the Carburetor

    • 1). Replace the air cleaner tube and assembly. Make sure all clamps are tightened.

    • 2). Put the fuel line back onto the carburetor. Bolt the carburetor to the motorcycle. The bolts should be tightened by hand and then using a socket.

    • 3). Remove the clamp that was holding the fuel line shut. Turn the fuel supply lever to the 'On' position.

    • 4). Drive the motorcycle a short distance to check the idle speed and rpm gauge while driving.

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