High Performance Valve Springs for the Kawasaki:
GPZ 1100
Z1000
Z900
KZ750 / GPZ 750 (76-85)
KZ650 (76-85)
May fit other models.
 
The original valve springs are made of round wire. ABUSO valve springs for these Kawasaki engines are made of Oval wire (outer spring) which is a far superior solution enabling higher forces and spring pressures with lower stress (more durability) as well as more valve lift as a consequence of a reduction in spring solid length.
Oval wire is the latest and most significant development in valve spring technology and is used by OEM manufacturers in their highest performance models.
 
Double Valve Spring Kit includes 8 Outer springs (oval wire) + 8 Inner springs (round wire). 
Compatible with all other stock parts, including our Shim under conversion retainers.
 
Valve Spring Specifications:
•    Installed Height: 32,9mm (same as stock)
•    Seat Pressure: 87lbs / 38,6 Kgf
•    Open Pressure (11mm): 214lbs / 95,3 Kgf
•    Max. Recommended Lift: 0,435” / 11,0mm
 
ABUSO Valve Springs are ideal for modified engines providing higher seat and open pressures while allowing for more valve lift. This ensures better valve control when using more aggressive camshaft profiles and increased RPM and valve lift.

ABUSO Springs are made from Super Clean oil-tempered Chrome Silicon Vanadium Steel Alloy sourced from Japan, especially intended for the manufacture of valve springs requiring very high fatigue properties. Fatigue resistance is further improved by multistage heat treatment and shot peening.
Our springs are Progressive Wound to optimize spring dynamics and avoid harmonic resonance that can lead to valve float and premature valvetrain wear.

We also offer a valve spring shim kit to adjust the installed height according to the engine builder preference. Shim kit has 16 shims (16 x 1,0mm).
 
We also have Stainless Steel Valves, Titanium Retainers (stock and shim under) and Bronze Guides for the Kawasaki Z and GPZ aircooled engines.