Boyesen Supercooler Water Pump Cover & Impeller Kit (Black) WPK-31B - Yamaha YZ125 1998-2004

Product Description

The Boyesen WPK-31B Supercooler Water Pump Cover and Impeller Kit is engineered to enhance the cooling system performance of your Yamaha YZ125. By increasing coolant velocity across all operating rpm ranges, this high-flow system ensures your engine runs cooler and maintains a far more consistent temperature during hard motos and high-rpm riding.

Cast from investment aluminum and finished in a durable black powder coat, the Supercooler kit features a patented hydrodynamic nautilus-style impeller. This design optimizes fluid flow dynamics to reduce cavitation, helping prevent heat-induced power loss and extending overall engine life on your 2-stroke machine.

Top Features: Boyesen Supercooler Kit

• Investment-cast aluminum water pump cover and impeller combo engineered specifically for maximum cooling efficiency.
• Patented nautilus-style impeller designed for hydrodynamic efficiency and reduced coolant cavitation.
• Increases coolant flow across all rpm ranges to maintain lower, more stable engine operating temperatures.
• Durable black powder-coated finish provides maximum corrosion resistance and a clean look.

Please review the detailed compatibility data below to ensure an exact fitment match for your dirt bike before finalizing your purchase.

Fitment List

Frequently Asked Questions

Q: How does the Boyesen Supercooler improve engine cooling on my YZ125?
A: The Supercooler replaces the restrictive stock water pump cover and impeller with a hydrodynamic nautilus-style impeller and high-flow cover, increasing coolant flow rate across all rpm ranges to lower engine operating temperatures.

Q: Does this kit include both the cover and the impeller?
A: Yes, the WPK-31B is a complete kit that includes both the aluminum water pump cover and the patented impeller.

Q: Why is lowering engine temperature important on a 2-stroke dirt bike?
A: Lowering operating temperatures prevents thermal fade, keeps power delivery consistent throughout long motos, and helps extend top-end component life.

Expert Pro-Tip: When installing your new water pump cover and impeller, always thoroughly flush the cooling system and clean all gasket mating surfaces completely. Take care to bleed all trapped air from the system upon refilling, as air pockets can cause localized hot spots and compromise overall cooling performance.

Recommended Pairings:

• Yamaha YZ125 Performance Parts & Upgrades
• Yamaha 2-Stroke Performance Parts
• High-Performance Coolants & Chemicals

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