Wiseco VSK4 Premium 8.90mm OD Valve Shim kit 8.90 millimeter outer diameter valve shim kit contains 3 of different thicknesses 8.90 millimeter shim kits fit most KTM 250F and 450F motors These kits are expertly manufactured to OEM specifications with optimum materials To ensure long service life, each shim is heat treated and precision ground to exact sizes The perfect complement to Wiseco's complete line of valve train components