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    • Flat Ball Valve Adjustment Screws

    This product is manufactured exclusively by or for KEDO!

    Installation Instructions – K50163 Flatball Valve Adjustment Screws

    Important Hints

    • The balls inside the screws are loose and are only held by grease during installation. The grease will vanish after the engine starts.
    • Ensure the balls remain in place during installation.
    • The engine must be in good condition, especially valve ends.
    • These screws are for Yamaha SR500, TT500, XT500 only. They have been tested on these models — use in other engines is at your own risk.

    Installation Instructions (engine must be cold)

    1 Remove the fuel tank.

    2 Remove the valve covers and the generator cover.

    3 Turn the engine to top dead centre (TDC) after the intake valve has closed.

    4 Unscrew the locking nut and remove the original valve adjusting screws.

    5 Place a piece of paper between the valve and rocker arm to prevent the ball from falling into the engine during installation.

    6 Install locking nuts onto the new screws and screw into rocker arms, holding the balls in place with the paper. The flat end of the ball must face the valve ends.

    7 Screw the screws fully into rocker arms until the paper touches the valve. Then back off slightly to remove the paper.

    8 Adjust clearance according to the manual and re-check after tightening the locking nuts.

    9 If the feeler gauge is difficult to insert, back off the adjustment slightly.

    10 Apply a drop of oil to the valve tips before startup.

    11 Reassemble generator cover, valve covers, and fuel tank.

    12 On startup, listen for abnormal noises and re-adjust clearance if necessary.

    ✅ Maintenance: Check and adjust valve clearance after 100 km, again at 3000 km, and every 5000 km thereafter.

    All information provided to the best of our knowledge, but without guarantee.