Kibblewhite Precision KPMI High Perf. OEM Spring Kit Steel 0.425" Lift, 40-41120 fits 2008-2009 Kawasaki Ninja ZX10R ZX1000E / 2010 Kawasaki Ninja ZX10R ZX1000F

KPMI® High Performance Spring kits are designed to work with the OEM retainer, and in most cases with the OEM spring base and /or shim. In many cases we do offer a lightweight, high performance FEA designed retainer as an option. All KPMI® valve springs are designed in house using sophisticated, proprietary design and simulation software programs. Our engineers, software, and over 75 years of experience enable us to determine critical characteristics including stress, natural frequency, system harmonics, and fatigue life. Our spring manufacturing partners are U.S based companies that are ISO certified. The Super-Clean Chrome-Silicon valve spring wire we use is traceable back to Kobe Japan where some of the best spring wire in the world is manufactured. Each spring goes through a rigidly controlled heat treatment, stress relief, and shot peening process. Combining our design, simulation, and manufacturing protocols with this premium quality valve spring wire allows KPMI® to supply you with the best possible valve.