
9 - 4
TRBL
SHTG
OVERHEATING/OVER COOLING/
FAULTY BRAKE
OVERHEATING
OVERHEATING
Ignition system
●
Improper spark plug gap
●
Improper spark plug heat range
●
Faulty CDI unit
Fuel system
●
Improper carburetor main jet
(improper setting)
●
Improper fuel level
●
Clogged air filter element
Compression system
●
Heavy carbon deposit
Engine oil
●
Improper oil level
●
Improper oil viscosity
●
Inferior oil quality
Brake
●
Brake drag
Cooling system
●
Low coolant level
●
Clogged or damaged radiator
●
Damaged or faulty water pump
●
Thermostat stays closed
OVER COOLING
COOLING SYSTEM
Thermostat
●
Thermostat stays open
FAULTY BRAKE
POOR BRAKING EFFECT
Disc brake
●
Worn brake pads
●
Worn disc
●
Air in brake fluid
●
Leaking brake fluid
●
Faulty master cylinder kit cup
●
Faulty caliper kit seal
●
Loose union bolt
●
Broken brake hose and pipe
●
Oily or greasy disc/brake pads
●
Improper brake fluid level
Summary of Contents for YFM660RN
Page 1: ...YFM660RN YFM660RNC SERVICEMANUAL LIT 11616 14 21 5LP 28197 E0 ...
Page 33: ...2 11 SPEC Cylinder head tightening sequence Item Standard Limit MAINTENANCE SPECIFICATIONS ...
Page 45: ...2 23 SPEC OIL FLOW DIAGRAMS 1 Oil tank 2 Oil pipe 2 3 Oil pipe 1 OIL FLOW DIAGRAMS ...
Page 110: ...3 54 CHK ADJ CHECKING THE BATTERY Charging method using a variable voltage charger ...
Page 111: ...3 55 CHK ADJ CHECKING THE BATTERY Charging method using a constant voltage charger ...
Page 327: ...YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN PRINTED IN U S A ...