1999-2004 Honda TRX400EX Fourtrax Service Manual

Honda TRX400EX Fourtrax 1999–2004 Service Documentation

• Covers 1999–2004 Honda TRX400EX Fourtrax all-terrain vehicles equipped with the 397 cc single-cylinder dry-sump engine
• Official OEM publication P/N 61HN100 (referencing page 3-1 for technical specifications and maintenance standards)
• Contains 47 exploded-view diagrams and 14 technical torque-value tables for frame, engine, and electrical sub-assemblies
• Delivered as a direct download the moment payment clears
• File link appears in your order confirmation straight away
• Page spreads stay legible when printed at original size
• Indexed PDF search covers every chapter and appendix
• This 1999–2004 Honda TRX400EX publication serves as the primary factory reference for the entire TRX400EX model run, including specific decompressor assembly and high-altitude carburetor tuning parameters not found in general owner literature

Structural and Maintenance Scope

The 1999–2004 Honda TRX400EX service manual provides a complete reference for the maintenance and assembly of all major vehicle systems. The document begins with a safety overview and identification section covering VIN, engine, and frame serial number locations. Detailed chapters follow for the frame and body panels, including removal and installation of the seat, fenders, and fuel tank heat shields. Engine-focused chapters document the cylinder head, valve train, cylinder and piston assemblies, clutch and gearshift linkages, and alternator components. The electrical section covers ignition, charging, and lighting systems with detailed wiring schematic references.

Additional coverage in the 1999–2004 Honda TRX400EX publication describes the lubrication system, including oil pump inspection and strainer maintenance protocols. The fuel system section documents the carburetor configuration, including jetting specs for standard and high-altitude riding conditions. Chassis maintenance is also addressed with sections on wheel, suspension, and steering system care. Owners can refer to what an OEM service publication covers to see how factory documentation is organized for long-term vehicle maintenance and troubleshooting.

Technical Preview and Reference Values

This manual details specific clearances and capacities for the 397 cc powerplant. Intake valve clearance is set at 0.10 mm (0.004 in), while the exhaust valve clearance is specified at 0.12 mm (0.005 in). Engine oil capacity is documented at 1.8 liters after draining. The carburetor uses a #148 main jet as the standard factory setting for low-altitude operation. Piston-to-cylinder clearance is defined within the standard range of 0.015–0.050 mm. A complete list of torque values is provided, such as 44 N-m for cylinder head nuts and 108 N-m for the clutch center lock nut. All technical data in this document is provided for reference only—qualified technicians and the original OEM documentation remain the authoritative source for any hands-on work. An official 263-page Honda OEM service manual covering the 1999–2004 TRX400EX, documenting engine, chassis, electrical, and fuel system specifications for the four-stroke Fourtrax sport ATV line.

Document Reference: 1999–2004 Honda TRX400EX Service Manual