YX & ZS Valve Shim Upgrade
 
These sit under the valve spring against the cylinder head casting.
 
Fits:
ZS Engines - 2 valve
YX Engines - 2 valve
 
Spec:
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