Yamaha XT660R S Service Manual

9 - 4
TRBL
SHTG
OVERHEATING/OVERCOOLING/
POOR BRAKING PERFORMANCE
EAS00855
OVERHEATING
ENGINE
Clogged coolant passages
• Cylinder head and piston
• Heavy carbon buildup
Engine oil
• Incorrect oil level
• Incorrect oil viscosity
• Inferior oil quality
COOLING SYSTEM
Coolant
• Low coolant level
Radiator
• Damaged or leaking radiator
• Faulty radiator cap
• Bent or damaged radiator fin
Water pump
• Damaged or faulty water pump
• Thermostat
• Thermostat stays closed
• Damaged hose
• Improperly connected hose
• Damaged pipe
• Improperly connected pipe
FUEL SYSTEM
Throttle body
• Faulty throttle body
• Damaged or loose throttle body joint
Air filter
• Clogged air filter element
CHASSIS
Brake(s)
• Dragging brake
ELECTRICAL SYSTEMS
Spark plug
• Incorrect spark plug gap
• Incorrect spark plug heat range
Ignition system
• Faulty ECU
EAS00856
OVERCOOLING
COOLING SYSTEM
Thermostat
• Thermostat stays open
EAS00857
POOR BRAKING PERFORMANCE
• Worn brake pad
• Worn brake disc
• Air in hydraulic brake system
• Leaking brake fluid
• Faulty brake caliper seal
• Loose union bolt
• Damaged brake hose
• Oil or grease on the brake disc
• Oil or grease on the brake pad
• Incorrect brake fluid level

Yamaha XT660R S Specifications

General

Displacement	660 cc
Bore x Stroke	100.0 mm x 84.0 mm
Compression Ratio	10.0:1
Fuel System	Fuel Injection
Ignition System	TCI
Starter System	Electric
Transmission System	5-speed
Final Drive	Chain
Front Suspension System	Telescopic forks
Front Tyre	90/90-21 M/C 54S
Rear Tyre	130/80-17 M/C 65S
Overall Width	865 mm
Overall Height	1, 230 mm
Seat Height	865 mm
Wheelbase	1, 505 mm
Wet Weight	181 kg
Fuel Tank Capacity	15 litres
Oil Tank Capacity	2.9 litres
Engine Type	Liquid-cooled, 4-stroke, single cylinder, SOHC
Maximum Power	48hp (35kW) @ 6, 000rpm
Frame	Steel diamond
Rear Suspension System	Swingarm, (link suspension)
Front Brake	Single 298mm disc, 2-piston caliper
Rear Brake	Single Disc, 245 mm