2004 Yamaha XT660R(S), XT660X(S) Service Manual (P/N 5VK1-AE1)

The Yamaha service manual 5VK1-AE1, MBK Industrie first edition dated December 2003, covers the 2004 XT660R(S) and XT660X(S) in the European, Australian, and Great Britain variants listed above.

• Engine repair: Engine removal, cylinder-head and valve service, piston inspection, camshaft timing, crankcase separation, and crankshaft installation.

• Clutch and transmission: Friction-plate inspection, clutch assembly, shift-fork and shift-drum checks, and transmission shaft disassembly.

• Brakes and chassis: Separate XT660R and XT660X front-brake sections, hydraulic bleeding, wheel-bearing replacement, fork overhaul, and suspension-linkage inspection.

• Cooling and lubrication: Radiator-cap and leak testing, thermostat checks, water-pump service, oil-pump inspection, and dry-sump oil-service procedures.

• Fuel injection: ECU self-diagnosis, fail-safe tables, sensor and actuator tests, fuel-pressure checks, throttle position sensor adjustment, and air induction system checks.

• Electrical diagnosis: Ignition, starting, charging, lighting, signaling, and immobilizer troubleshooting, supported by system circuit diagrams and a full wiring diagram.

Written primarily for Yamaha dealers and qualified mechanics, this manual assumes a basic understanding of mechanics and vehicle-repair techniques.

Engine Inspection, Timing, and Lubrication

Service data is organized across nine core chapters. Exploded views are paired with job charts, replacement symbols, and component-specific tightening specifications, including separate cylinder-head fastener and clutch boss nut entries.

Internal inspection covers valve-guide fit, piston-to-cylinder clearance, crankshaft runout, bearings, and oil seals. Camshaft installation cautions explain how incorrect crankshaft movement during assembly can cause damage or improper valve timing.

Dry-sump servicing distinguishes oil-level checks from oil changes and describes staged oil-tank filling. The lubrication chart traces pressure feed and scavenging through the oil tank, pumps, crankshaft, and transmission shafts. Special-tool illustrations identify the equipment needed for crankshaft installation and other internal work.

Model-Specific Brakes and Suspension Service

XT660R and XT660X brake differences remain separately identified in the pad and caliper sections, helping mechanics select the correct front-brake procedure. Fork data likewise distinguishes the models’ springs and oil quantities.

Fork disassembly notes warn that bottoming the inner tube into the outer tube can damage the oil-flow stopper. Rear-shock coverage includes removal, inspection, and replacement; the manual warns against opening the nitrogen-charged unit.

Brake-system repairs and work on hot, pressurized coolant require the manual’s safety precautions. Consult a qualified technician if the work exceeds your experience.

FI Fault Tracing and Throttle-Body Service

The diagnostic chapter links fault codes to probable causes, connector checks, and ECU restore methods. Its diagnostic-mode tables distinguish sensor readings from actuator tests, supporting fault isolation before a component is replaced.

Throttle-body coverage includes removal, cleaning, injector testing, and throttle position sensor adjustment; the manual specifically prohibits disassembling the throttle body itself. Fuel-pressure testing identifies pressure gauge 90890-03153 and adapter 90890-03176.

Air induction system diagrams show the reed valve, air cut-off valve, and exhaust-port connections. Separate cooling system diagrams illustrate the radiator, reservoir, water pump, and hose connections.

Electrical Testing and Immobilizer Registration

Electrical component-location views and cable-routing drawings support circuit testing. The starting circuit cut-off diagram explains the relationship between the neutral, clutch, and sidestand switches. Battery charging charts accompany the charging-system checks.

The A.C. magneto and starter clutch receive mechanical inspection procedures, while the starter motor section covers internal checks and reassembly.

Immobilizer coverage includes its circuit diagram, key-code registration, malfunction-code tables, and a replacement-parts matrix. Losing the red code re-registering key does not prevent registered standard keys from starting the engine, but later code registration can require replacement of the ECU, main switch, and immobilizer unit.

Sample Valve, Compression, and Coolant Specifications

Cold valve-clearance specifications distinguish 0.09–0.13 mm intake from 0.16–0.20 mm exhaust, with the adjustment section explaining the required engine position.

Standard compression is specified at 650 kPa at sea level and 800 r/min. Cooling specifications list a radiator capacity of 1.00 L and a separate coolant reservoir capacity of 0.25 L.

Text Search, Chapter Bookmarks, and Wiring Detail

Finding text and reading diagrams: The service text is searchable, and embedded bookmarks link to all nine chapters and the full wiring diagram. Small wire-color codes and connector labels require zooming for comfortable reading.

One printable English-language PDF contains 463 pages, including one additional front-matter page and six blank pages.