2005–2008 Honda TRX500 FA/FGA Rubicon ATV Service Manual (P/N 61HN252)

This Honda service manual, P/N 61HN252, covers the 2005–2008 TRX500 FA/FGA Rubicon series, including standard and GPScape versions.

• Engine repair: Engine removal and installation, cylinder-head and valve service, camshaft inspection, and cylinder/piston removal, measurement, and reassembly.

• Hondamatic diagnostics: Problem-code retrieval and erasure, initial setting, angle-sensor and control-motor testing, and gear-position switch diagnosis.

• Clutch and sub-transmission: Centrifugal-clutch disassembly and inspection, sub-transmission rebuild procedures, and gearshift linkage adjustment.

• Differential and final drive: Front differential and rear final-drive disassembly, bearing replacement, backlash inspection, and gear-tooth contact checks.

• Brakes and chassis: Front hydraulic brake service, rear drum-brake repair, suspension-arm and ball-joint work, steering service, and swingarm bearing replacement.

• Electrical systems: Ignition and charging tests, starter-motor overhaul, selectable 4WD troubleshooting, GPScape receiver diagnosis, and variant-specific wiring diagrams.

The manual is written for qualified professional technicians with shop safety training and the tools and equipment required for the work.

Hondamatic Diagnosis and Transmission Scope

The diagnostic sections distinguish current and stored problem codes, explain indicator blink patterns, and provide circuit checks for the TP sensor, angle sensor, control motor, ESP switches, and ECM. The initial-setting procedure addresses component replacement and work involving the throttle cable or TP-sensor connection.

Mechanical troubleshooting relates drive-performance symptoms to oil level, oil pressure, centrifugal-clutch condition, and transmission-bearing checks. This helps separate lubrication and clutch faults from problems within the automatic transmission.

Transmission repair boundary: The manual covers removal and installation of the automatic transmission unit but directs replacement of a faulty unit as an assembly; it specifically prohibits internal disassembly. Sub-transmission service requires engine removal, while its external shift linkage can be serviced in the frame.

Engine, Clutch, and Lubrication Work

Cylinder-head coverage extends to valve-guide replacement, valve-seat inspection and refacing, rocker-arm inspection, and camshaft service. Cylinder and piston procedures include wear measurements and ring installation; these top-end assemblies can be serviced with the engine installed.

The centrifugal-clutch section provides lining, drum, spring, and sprag-clutch inspection criteria, plus dedicated holder and puller references. The lubrication section adds oil-pressure testing, pump inspection, and a Lubrication System Diagram.

The cylinder-head-cover instructions warn that incorrect rocker-arm alignment with the push rods can cause severe engine damage.

Carburetor Service and Regional Differences

Carburetor coverage distinguishes VE6AE for A/CM types from VE6AF for U types, with separate treatment of the U-type air cut-off valve. Disassembly, diaphragm inspection, float-level checks, pilot-screw adjustment, carburetor-heater testing, and high-altitude adjustment are documented.

Cooling System Tests and Service

The System Flow Pattern supports radiator-cap and cooling-system pressure tests, thermostat inspection, coolant replacement and air bleeding, and water-pump removal and installation.

Honda also identifies a specific coolant-related repair risk: silicate inhibitors can cause premature water-pump seal wear or block radiator passages.

Final Drive, Selectable 4WD, and Chassis

Front and rear gear-case procedures explain shim selection and tooth-contact assessment alongside backlash checks. Selectable 4WD diagnosis uses its System Diagram and problem-code charts to trace vehicle-speed-sensor, system-voltage, and front final-clutch faults.

Chassis coverage includes hydraulic brake bleeding, master-cylinder and caliper service, rear brake shoes, wheel bearings, and steering alignment. Raised-vehicle work and brake repairs require the support and safety precautions specified in the manual.

Electrical Tests and GPScape Coverage

The Hondamatic Circuit Diagram, ECM connector views, cable and harness routing diagrams, and exploded component views support circuit tracing and reassembly. Electrical test specifications and troubleshooting tables cover ignition, charging, starting, meters, and switches.

GPS receiver procedures address communication errors, extended start-up time, supply and backup voltage, and receiver replacement. Full wiring diagrams distinguish standard and GPScape versions, regional types, and the manual’s “05/06” and “After 06” configurations.

A Preview of Adjustment and Inspection Values

These examples represent a small selection of the service data accompanying the procedures.

Valve clearances are 0.15 mm intake and 0.23 mm exhaust, checked with the engine cold below 35°C. Throttle-lever free play is specified as 3–8 mm.

Oil-pump inspection gives a rotor-tip clearance service limit of 0.20 mm. Ignition-pulse-generator testing specifies a minimum peak voltage of 0.7 V during starter-motor cranking, with normal cylinder compression and the spark plug installed.

PDF Search, Page Bookmarks, and Diagram Detail

Search and diagram limitations: Most service text is searchable, but the contents page and labels within the full wiring diagrams are not. Embedded bookmarks identify individual pages numerically rather than by chapter name. Some small connector and wire-color labels remain difficult to read even when enlarged.

Supplied as one printable, 540-page PDF. The total already includes 19 blank or memo pages; these are not additional pages.