Honda TRX500FA/FGA Rubicon ATV Service Manual, 2005–2008 (P/N 61HN253)

This Honda service manual, P/N 61HN253, covers the 2005–2008 TRX500 FA/FGA Rubicon series, including Standard and GPScape versions.

Searchable Service Text and Numbered Bookmarks

Text search and wiring detail: Most service text is searchable, and numbered bookmarks open individual pages. The main contents page and the labels inside the full wiring diagrams are image-based. Some small connector pin and wire-color labels remain difficult to read when enlarged.

The download is one printable, English-language 540-page PDF, including 3 blank pages and 16 memo pages.

Engine Repair, Hondamatic Diagnostics, and Driveline Service

This selection of service topics includes major repairs and diagnostic procedures. The manual also covers spark arrester service and recoil starter repair.

• Engine repair: Engine removal and installation, cylinder-head and valve service, camshaft inspection, and cylinder and piston removal, measurement, and reassembly.
• Hondamatic diagnostics: Problem-code retrieval and clearing, 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.

Honda wrote the manual for qualified service technicians with shop safety training and access to the tools and equipment required for the work.

Hondamatic Faults and Transmission Repair Scope

The diagnostic sections distinguish current and stored problem codes, explain indicator blink patterns, and cover circuit checks for the throttle position (TP) sensor, angle sensor, control motor, ESP switches, and ECM. The initial-setting procedure covers when recalibration is required after component work, including when the TP sensor or throttle cable has been disconnected from the carburetor.

The troubleshooting charts help technicians distinguish lubrication and clutch faults from faults inside the Hondamatic unit. For drive-performance complaints, Honda documents checks for oil level, oil pressure, centrifugal-clutch condition, and transmission-bearing condition.

Automatic transmission and sub-transmission: Honda provides automatic transmission unit removal and installation procedures and specifies assembly replacement if the unit fails. The sub-transmission has its own internal repair procedures and requires engine removal. Its external shift linkage can be serviced with the engine in the frame.

Top-End, Clutch, and Oil System Work

Top-end procedures include valve-guide replacement, valve-seat inspection and refacing, rocker-arm inspection, cylinder and piston wear measurements, and ring installation. These assemblies can be serviced with the engine installed. The cylinder-head-cover section warns that misaligning the rocker arms and push rods can cause severe engine damage.

The centrifugal-clutch section provides inspection criteria for the lining, drum, springs, and sprag clutch, plus holder and puller references. The lubrication chapter includes an oil flow diagram, oil-pressure testing, and pump inspection. Torque tables and special-tool references help technicians prepare for disassembly and reassembly.

Carburetor and Cooling Service

Carburetor coverage distinguishes VE6AE for A and CM types from VE6AF for U types. Procedures cover disassembly, diaphragm inspection, float-level checks, pilot-screw adjustment, and carburetor-heater testing. The U type has a separate air cut-off valve procedure. High-altitude adjustment applies to A and CM types.

The cooling-system flow diagram accompanies radiator-cap and system pressure tests, thermostat inspection, coolant replacement and bleeding, and water-pump removal and installation. Honda identifies silicate inhibitors as a cause of premature water-pump seal wear or blocked radiator passages.

Final Drive, Brakes, and Selectable 4WD

Front differential and rear final-drive procedures explain shim selection and tooth-contact checks. Chassis coverage includes front hydraulic brake bleeding, master-cylinder and caliper service, rear brake shoes, wheel bearings, and steering alignment.

The selectable 4WD system diagram and problem-code charts help trace vehicle-speed-sensor, system-voltage, and front final-clutch faults.

Electrical Tests and GPScape Wiring

ECM connector views and cable and harness routing diagrams support circuit tracing. Exploded views show component order during reassembly. Test specifications and troubleshooting tables cover ignition, charging, starting, meters, and switches.

GPScape receiver procedures cover communication errors, slow startup, supply and backup voltage, and receiver replacement. The full wiring diagrams distinguish Standard and GPScape configurations. For models after 2006, the GPScape diagram is labeled for A and CM types.

Sample Valve, Throttle, Oil Pump, and Ignition Values

Cold valve clearance is 0.15 mm intake and 0.23 mm exhaust below 35°C. Throttle-lever free play is 3–8 mm, measured at the tip of the lever.

The oil pump rotor tip clearance has a service limit of 0.20 mm. The ignition pulse generator peak-voltage test specifies a minimum of 0.7 V during starter-motor cranking with normal cylinder compression and the spark plug installed.