Accelerate coolant circulation and prevent engine thermal soak under heavy load. Precision-engineered by KOSO in Taiwan, this high-efficiency water pump upgrade delivers maximized flow rates and enhanced cooling stability for Yamaha 125cc–155cc+ liquid-cooled engine platforms.
Detailed Product Description
Protect your engine internals and maintain consistent peak horsepower with the KOSO High-Efficiency Water Pump (NH073000). Specifically engineered for Yamaha’s modern liquid-cooled 4-valve engine architecture, this performance water pump upgrade resolves common cooling limitations found in factory setups during aggressive throttle riding, prolonged track days, or hot-weather stop-and-go commuting.
Featuring an aerodynamically optimized impeller blade profile, the KOSO water pump significantly increases coolant flow velocity through the cylinder block and radiator core. This accelerated heat transfer prevents localized hotspotting and thermal power loss (engine thermal soak).
Available in two bore specifications to match your exact performance build:
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30mm Specification: Optimized for stock factory displacements (125cc–155cc) up to mild street bore kits (under 180cc), delivering quick cooling recovery without adding excessive mechanical drag.
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38mm Specification: Engineered specifically for aggressive big-bore engines, high-compression builds (180cc–240cc), and competitive racing applications that demand high-volume coolant throughput.
Engineered to OEM tolerances, it installs directly into factory engine casing locations for a clean, reliable, and leak-free upgrade.
Key Features and Performance Benefits
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Optimized High-Flow Impeller: Re-profiled vane geometry accelerates coolant circulation, lowering operating temperatures and preventing cylinder thermal expansion fatigue.
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Eliminates Thermal Soak: Keeps engine cylinder head temperatures stable during sustained high-RPM operation, ensuring zero loss of top-end pulling power.
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Two Dedicated Size Options:
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30mm: Perfect for stock displacements (125cc–155cc) and mild street upgrades.
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38mm: Purpose-built for big-bore conversions (180cc–240cc) and competition setups.
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Precision CNC & Molded Tolerances: Engineered to withstand continuous high coolant pressure and extreme engine bay heat without shaft seal failure.
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Direct Bolt-On Fitment: Matches factory mounting points and coolant plumbing connections cleanly with no engine case modification required.
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Authentic Made in Taiwan Quality: Precision designed and manufactured by KOSO to guarantee lasting reliability on the street and track.
Specifications
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Brand: KOSO
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Origin: Made in Taiwan
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Product Code: NH073000
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Category: Performance / Cooling & Lubrication System / Water Pump
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Available Size Variants: 30mm / 38mm
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Fitment Compatibility:
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Yamaha Cygnus XR 125 / 155 (7th Generation)
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Yamaha Cygnus Gryphus 125 (6th Generation)
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Yamaha Zuma 125 (2022+ Liquid-Cooled / US Models)
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Yamaha FORCE 2.0 155 / X FORCE 155 /JP TW Models)
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Yamaha AUGUR 155
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Yamaha NMAX 155 (2020+ / 2022+)
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Yamaha AEROX 155 (2021+)
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Package Includes: 1x KOSO High-Efficiency Water Pump Assembly, Installation Gaskets/O-rings