This page covers used OEM parts for the Kawasaki KFX400, the sport ATV produced from 2003 through 2006. The KFX400 shares its 398cc liquid-cooled single-cylinder engine with the Suzuki LT-Z400 (QuadSport Z400) and Arctic Cat DVX400, as all three were built through a manufacturing partnership. The KFX400 delivers competitive sport-quad performance with a five-speed manual transmission, chain drive, and aggressive handling geometry. Sun Coast Cycle Sports carries inspected KFX400 parts, each individually cataloged and shipped from Florida.
KFX400 generation and parts compatibility
The KFX400 was produced as a single generation from 2003 through 2006 with minimal changes during its production run. The 398cc DOHC single-cylinder engine is shared with the Suzuki LT-Z400 and Arctic Cat DVX400, as these three ATVs were manufactured through a Suzuki-Kawasaki-Arctic Cat joint venture. Engine internals, carburetor, electrical charging system, and many drivetrain components cross over between all three brands.
The frame, suspension geometry, bodywork, and some chassis components differ between the KFX400, LT-Z400, and DVX400, as each manufacturer applied their own styling and ergonomic preferences. However, the engine and transmission are functionally identical across all three. Parts interchange freely across all 2003-2006 KFX400 model years.
The KFX400 does not share parts with the later KFX450R (2008-2014), which uses a completely different Kawasaki-designed 449cc engine with fuel injection.
Common KFX400 failure points and replacement parts
Valve adjustment: The DOHC single-cylinder engine requires periodic valve clearance checks and adjustment, typically every 500-1,000 miles depending on riding intensity. Shim-under-bucket valve adjustment kits are a common service item.
Carburetor jetting: The stock Mikuni carburetor is frequently rejetted by owners for aftermarket exhaust and air filter modifications. Jet kits, needles, and complete carburetor assemblies are high-demand parts.
Chain and sprocket wear: Sport ATV riding accelerates chain and sprocket wear. Replacement every 1,000-2,000 miles is typical for aggressive riders.
Crash and race damage: The KFX400's role as a sport quad means it gets ridden hard. A-arm components, tie rods, axle carriers, plastics, and nerf bars are commonly replaced after crashes and aggressive riding.
Electrical starter issues: The electric starter motor and related solenoid are known to develop issues, particularly on machines used in dusty or wet conditions.
Cooling system: The radiator on the KFX400 is exposed and vulnerable to damage from rocks and debris. Radiator replacements, fan assemblies, and coolant hoses are periodic parts requests on machines used in rocky terrain.
Commonly replaced KFX400 parts
- Chain and sprocket set
- Carburetor and jet kit
- A-arm components and tie rods
- Plastic fenders and bodywork
- Brake pads and rotors
- Starter motor and solenoid
- Air filter
- Exhaust system
Frequently asked questions
Q: Does the KFX400 share its engine with the Suzuki LT-Z400?
Yes. The KFX400, Suzuki LT-Z400 (QuadSport Z400), and Arctic Cat DVX400 all share the same 398cc DOHC single-cylinder engine manufactured through a joint venture. Engine internals, carburetor, and many drivetrain components cross over between all three. This gives parts buyers three donor platforms when sourcing engine components.
Q: Does the KFX400 share parts with the KFX450R?
No. The KFX450R (2008-2014) uses a completely different Kawasaki-designed 449cc fuel-injected engine. The frame, suspension, and bodywork are also different. The KFX400 and KFX450R are separate platforms with no meaningful parts compatibility.
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