Segment:
Dual-sport / Supermoto motorcycle.
Competitors:
Honda XR650L, Kawasaki KLR650, Suzuki DR650SE, KTM 640/690 Enduro/SMC.
Model Variants:
XT660R (dual-sport oriented) and XT660X (supermoto/street oriented).
Engine Characteristics:
Characterized by its torquey single-cylinder engine, robust build, and versatility.
Purpose:
To provide comprehensive guidance for the maintenance, repair, and servicing of the Yamaha XT660R and XT660X models.
Engine:
Complete disassembly, inspection, assembly, timing, valve adjustment, cooling system, lubrication system, fuel injection system, exhaust system.
Transmission:
Clutch operation, gearbox inspection, gearshift mechanism, lubrication, maintenance.
Chassis:
Frame inspection, suspension (front forks, rear shock absorber), steering system, swingarm, wheel bearings, hubs.
Brakes:
Front and rear brake system maintenance, hydraulic system, caliper inspection and service, brake disc specifications, bleeding procedures.
Electrical System:
Complete wiring diagrams, ignition system, starting system, charging system (stator, rectifier/regulator), lighting system, instrumentation, fuses, relays, battery maintenance, troubleshooting.
Fuel System:
Fuel tank maintenance, fuel pump, fuel filter replacement, fuel injection system (throttle body, injectors, ECU mapping considerations).
Cooling System:
Radiator, coolant specifications, thermostat operation, fan operation, flushing and filling procedures.
Exhaust System:
Muffler inspection, catalytic converter details, exhaust gasket replacement.
Bodywork:
Fairings, seat, fuel tank cover, fenders, graphics.
Maintenance:
Scheduled maintenance (oil changes, filter replacements, chain adjustment, brake checks, spark plug replacement, air filter cleaning/replacement, coolant checks).
Troubleshooting:
Diagnostic procedures for common and complex issues, symptom-based troubleshooting guides.
Repair:
Step-by-step repair instructions for all major components and systems.
Disassembly Assembly:
Detailed instructions for complete disassembly and reassembly of the motorcycle and its components.
Specifications Settings:
Torque specifications for all fasteners, valve clearances, idle speed adjustments, suspension settings, tire pressures.
Depth:
Comprehensive coverage from basic routine maintenance to advanced engine rebuilds and electrical system diagnostics. Suitable for both home mechanics and professional workshops.
Engine Type:
Single-cylinder, 4-stroke, liquid-cooled, SOHC, 4-valve.
Displacement:
660 cc (660 cm³)
Bore X Stroke:
100 mm x 84 mm
Compression Ratio:
10.0:1
Horsepower:
Approx. 47.5 HP (35 kW) @ 6,000 RPM (varies slightly by region/year)
Torque:
Approx. 60 Nm (44.3 lb-ft) @ 5,250 RPM (varies slightly by region/year)
Fuel Delivery:
Electronic Fuel Injection (EFI) with Mikuni throttle body.
Fuel Type:
Unleaded gasoline, minimum 91 RON (Research Octane Number).
Ignition System:
TCI (Transistor Controlled Ignition) with electronic advance.
Lubrication System:
Wet sump with oil cooler.
Cooling Method:
Liquid-cooled.
Length:
XT660R: 2145 mm (84.4 in) / XT660X: 2130 mm (83.9 in)
Width:
XT660R: 830 mm (32.7 in) / XT660X: 830 mm (32.7 in)
Height:
XT660R: 1220 mm (48.0 in) / XT660X: 1165 mm (45.9 in)
Seat Height:
XT660R: 875 mm (34.4 in) / XT660X: 865 mm (34.1 in)
Wheelbase:
XT660R: 1440 mm (56.7 in) / XT660X: 1445 mm (56.9 in)
Wet Weight:
Approx. 181 kg (399 lbs) for XT660R, Approx. 183 kg (403 lbs) for XT660X (includes all fluids and fuel).
Fuel Capacity:
15 Liters (3.96 US gal)
Oil Capacity:
Refer to manual for specific oil capacity with filter change and without filter change.
Instrument Cluster:
Digital multi-function instrument cluster with speedometer, tachometer, odometer, trip meters, clock, fuel gauge, and warning lights.
ABS:
ABS was an optional feature on some models/markets, and not standard on all versions covered by this manual.
Connectivity Features:
N/A (basic motorcycle, no advanced connectivity features).
Oil Change Interval:
Refer to manual, typically every 5,000 - 10,000 km (3,000 - 6,000 miles) or 6-12 months, whichever comes first.
Valve Clearance Interval:
Refer to manual, typically every 20,000 - 30,000 km (12,000 - 18,000 miles).
Spark Plug Replacement:
Refer to manual, typically every 10,000 - 15,000 km (6,000 - 9,000 miles).
Engine Oil Type:
Yamalube 4 (or equivalent) SAE 10W-40, API SG or higher, JASO MA certified.
Coolant Type:
High-quality ethylene glycol-based coolant with antifreeze and anti-corrosion additives. Mixture of 50% coolant and 50% distilled water.
Gear Oil Type:
Yamalube Gear Oil (or equivalent) SAE 80 API GL-4.
Common Issues:
Stalling at low RPMs (often related to ECU mapping or idle speed), stator failures, regulator/rectifier issues, occasional clutch judder. Manual provides troubleshooting for these.
Heritage:
Yamaha has a long history of producing reliable and capable off-road and dual-sport motorcycles, including the legendary XT series.
Evolution:
The XT660 platform was developed as a modern, fuel-injected successor to older XT models, offering improved performance and emissions compliance. The R variant is geared towards mixed-surface riding, while the X is a factory supermoto conversion.
Production Period:
2004-2016.
Manufacturing Location:
Primarily manufactured in Japan.
