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YX & ZS Valve Shim Upgrade


These sit under the valve spring against the cylinder head casting.



  • ZS Engines - 2 valve
  • YX Engines - 2 valve



  • SHIM O.D = 22.86mm
  • SHIM I.D = 16.80mm
  • SHIM THICKNESS = Choice Of


Please Note:

  • Increasing valve spring preassure can increase engine performance and RPM. It can also create more wear on other components. Too much preassure can create damage to components and also a loss of power.

Item Includes:

  • 2x Shim Washers


YX & ZS Valve Shim Upgrade

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