1998–2004 Honda FourTrax Foreman 450 TRX450S/FM & TRX450ES/FE ATV Repair & Service Manual (P/N 61HN006)

This Honda service manual covers the 1998–2004 FourTrax Foreman 450 TRX450S/FM and TRX450ES/FE, with 26 sections addressing maintenance, mechanical repair, chassis service, and electrical diagnosis.

• Engine repair: Engine removal and installation, cylinder-head overhaul, piston inspection, camshaft service, and crankshaft, balancer, and transmission disassembly.

• Clutches and drivetrain: Centrifugal and change-clutch service, gearshift linkage repair, front differential overhaul, rear final-drive service, and gear-contact checks.

• Fuel and lubrication: CV carburetor disassembly, pilot-screw and high-altitude adjustments, oil-pump inspection, oil-cooler service, and routine maintenance procedures.

• Suspension, steering, and brakes: Wheel-bearing and ball-joint replacement, swingarm service, steering alignment, hydraulic front drum-brake repair, bleeding, and mechanical rear-brake service.

• Electrical diagnosis: Battery and charging tests, ignition checks, starter-motor overhaul, lighting and meter troubleshooting, cable routing, and model-specific wiring diagrams.

• ESP and selectable 4WD: Electric Shift Program troubleshooting for ES/FE models, angle-sensor and control-motor tests, and final-clutch control-system diagnosis for FM/FE models.

Honda wrote this manual for readers who already have basic knowledge of maintenance on Honda motorcycles, scooters, or ATVs.

Engine, Clutch, and Transmission Repair

The engine chapters cover compression testing, valve-guide replacement, valve-seat refacing, and cylinder and piston inspection. Cylinder-head, cylinder, and piston service can be performed with the engine in the frame; crankshaft and transmission repair requires engine removal and crankcase separation.

Separate assembly illustrations distinguish the S/FM transmission components from the ES/FE versions. Clutch coverage treats the centrifugal clutch and multi-plate change clutch separately, alongside the alternator, starter clutch, and gearshift linkage.

Lubrication-system drawings and crankcase-emission diagrams show the related oil and breather circuits. The maintenance section specifically warns that installing the oil filter backward can cause severe engine damage.

CV Carburetor Service and Adjustment

Carburetor coverage includes the starting enrichment valve, diaphragm/vacuum piston, jets, float valve, and air cut-off valve. The manual documents pilot-screw adjustment and high-altitude jetting, with an exploded assembly view identifying the internal components.

Float-level inspection specifies gauge 07401-0010000; the float itself is not adjustable. A separate service caution identifies pilot-screw seat damage caused by overtightening.

Differentials, Drive Shafts, and Chassis

Front differential procedures distinguish the earlier clutch-pack arrangement from the later face-cam and cam-follower design. Gear-tooth contact illustrations, backlash checks, shim selection, and limited-slip torque tests support differential inspection and assembly.

Front drive-shaft coverage includes inboard-joint disassembly and boot replacement. The outboard joint is not dismantled; the manual specifies shaft replacement when that joint is worn or damaged.

Chassis procedures extend to steering-shaft bearings, toe-out adjustment, swingarm pivot bearings, and front brake master- and wheel-cylinder service. Observe the manual’s precautions for vehicle support, fuel handling, exhaust ventilation, and battery gases.

ESP Fault Tracing and Selectable 4WD

The ESP chapter separates early-system troubleshooting from the later gear-indicator blink-code diagnosis. Its checks distinguish mechanical shifting problems from faults in the angle sensor, control motor, switches, connectors, wiring, and ECU, helping narrow down a no-shift complaint before components are replaced.

Selectable 4WD coverage addresses the front final clutch, its control unit, and the associated speed sensors. ESP and selectable-4WD system diagrams accompany the diagnostic charts; charging, ignition, starting, and cooling-fan circuits have their own inspection procedures.

Wiring coverage: The wiring chapter contains diagrams for the S, ES, FM, and FE variants. The separate Canadian FM/FE diagrams listed in the index are not included in this PDF.

Preview of Valve and Lubrication Specifications

Intake and exhaust valve clearance is specified at 0.15 mm with the engine cold, below 35°C/95°F.

Engine-oil capacity is listed as 2.0 liters after draining and 2.1 liters when the oil filter is changed. The engine-oil drain-bolt torque is 25 N·m.

For the post-2001 front differential, the maintenance procedure specifies 241 cm³ after draining.

Chapter Access, Diagram Detail, and PDF Contents

Bookmarks, search, and wiring detail: Chapter bookmarks are included, but the technical manual text is not searchable. Small wire-color and connector labels in the FM/FE diagrams remain blurred in places when enlarged. The first wiring diagram begins at PDF p. 466, one page before the wiring bookmark.

Supplied as one printable, 506-page English PDF: 483 manual pages, including the cover and 10 memo pages, and 23 nontechnical additional pages—two introductory pages and 21 pages at the end.