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Flat Ball Valve Adjustment Screws

Installation Instructions for K50163 Flatball Valve adjustment screws

Important Hints:

  • The Balls inside the screws are loose. They are retained in place by grease during installation. The grease will vanish quickly after starting the engine.
  • Make sure the balls stay in place during installation
  • The engine should be in good condition to get the best possible effect, particularly the valve ends should be in perfect condition.
  • These Valve Adjustment Screws are designed exclusively for Yamaha SR500 TT500 XT500 engines  and have been tested successfully, we do not advise use in other engines as we cannot assume liability, use in other engines will be at your own risk.

Installation Instructions (engine needs to be cold):

  1. Remove the Fuel Tank
  2. Remove the Valve Covers and the Generator cover
  3. Turn the engine to top dead centre after the Intake valve is closed
  4. Unscrew the locking nut and remove the valve adjusting screws
  5. Place a piece of paper between the valve and the rocker arm to prevent the ball from falling into the engine just in case it drops out of the adjustment screw during mounting
  6. Install locking nuts onto the adjustment screws then screw into rocker arms while holding the balls in place with the piece of paper. The flatted end of the balls need to point to the valve ends
  7. Screw the screws all the way into the rocker arms until the piece of paper touches the valve. then unscrew slightly to remove the paper
  8. Adjust the clearance according to the manual and check it after tightening the locking nuts
  9. Hint: If you find it difficult to put the feeler gauge beteen the screw and the valves, Back off the adjustment slightly
  10. Put a little oil on the valve tips to prevent lack of lubrication on start up
  11. Re-assemble the generator cover , valve covers and fuel tank
  12. Listen for noises when starting engine and re-adjust the clearance when needed
  13. Valve clearance should be checked and adjusted after 100 km and again after 3000 km, then check and adjust every 5000 km