Kibblewhite Top End Rebuild Kit with White Diamond Valves for Yamaha WR450F and YZ450F (80-81900)

Restore top-end performance with the Kibblewhite 80-81900 Top End Kit, engineered as a complete piston and valve service solution for select Yamaha WR450F and YZ450F applications. This kit combines matched internal components to support a reliable rebuild, including performance pistons, piston rings, piston pins, White Diamond® valves, valve springs, gaskets, seals, O-rings, and related installation hardware. The components are designed to work together as a system rather than as individually selected OEM replacements.
The pistons are machined from high-strength 2618 aluminum alloy and feature a performance skirt coating to promote smooth operation and durability in demanding riding conditions. The included piston rings, piston pins, and pin clips are matched to the piston kit for proper compatibility. White Diamond® valves provide a performance-focused upgrade for the cylinder head, while the complete gasket and sealing package helps simplify top-end assembly and service.
The Kibblewhite valve spring package includes lightweight racing springs, titanium retainers, dual springs, and heat-treated steel base washers. The springs are suitable for use with high-performance camshafts and are intended for applications requiring dependable valve control at elevated engine speeds. Before installation, verify vehicle fitment, engine configuration, and camshaft compatibility to ensure the components match the intended build.
This Kibblewhite top-end kit is not compatible with OEM components. Professional installation and careful inspection of cylinder, head, camshaft, and related engine parts are recommended during assembly. Use the Kibblewhite 80-81900 kit when replacing the complete top-end system and seeking coordinated piston, valve, spring, and sealing components for a Yamaha WR450F or YZ450F performance rebuild.

Features:

• Complete top-end service and rebuild kit with pistons, piston rings, piston pins, gaskets, valves, valve springs, seals, O-rings, and installation hardware

• 2618 aluminum alloy pistons with performance skirt coating for strength and reduced friction

• Matched pistons, rings, valves, piston pins, and pin clips designed to function together as a system

• White Diamond® valves for performance-oriented cylinder head service

• Lightweight racing valve spring kit with titanium retainers, dual springs, and heat-treated steel base washers

• Valve springs suitable for use with high-performance camshafts

• Not compatible with OEM components

• Application-specific fitment for select Yamaha WR450F and YZ450F models

Ships from Parts Unlimited.