TROUBLESHOOTING
9-3
Cooling system
1. Coolant
• Low coolant level
2. Radiator
• Damaged or leaking radiator
• Faulty radiator cap
• Bent or damaged radiator fin
3. Water pump
• Damaged or faulty water pump
• Damaged hose
• Improperly connected hose
• Damaged pipe
• Improperly connected pipe
Fuel system
1. Throttle body
• Damaged or loose throttle body joint
2. Air filter
• Clogged air filter element
Chassis
1. Brake(s)
• Dragging brake
Electrical system
1. Spark plug
• Incorrect spark plug gap
• Incorrect spark plug heat range
2. Ignition system
• Faulty ECU
• Faulty coolant temperature sensor
EASB29B380
OVERCOOLING
Cooling system
1. Coolant temperature sensor
• Faulty coolant temperature sensor
EASB29B381
POOR BRAKING PERFORMANCE
Chassis
1. Brake(s)
• Worn brake pad
• Worn brake disc
• Air in hydraulic brake system
• Leaking brake fluid
• Defective master cylinder kit
• Faulty brake caliper kit
• 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
EASB29B382
FRONT FORK OIL LEAKING
Chassis
1. Front fork
• Bent, damaged, or rusty inner tube
• Cracked or damaged outer tube
• Improperly installed oil seal
• Damaged oil seal lip
• Incorrect oil level (high)
• Loose damper rod assembly bolt
• Damaged damper rod assembly bolt copper
washer
• Cracked or damaged cap bolt O-ring
EASB29B383
FAULTY FRONT FORK LEGS
Chassis
1. Front fork
• Bent or damaged inner tube
• Bent or damaged outer tube
• Broken fork spring
• Bent or damaged damper rod
• Incorrect oil viscosity
• Incorrect oil level
EASB29B384
UNSTABLE HANDLING
Chassis
1. Handlebar
• Bent or improperly installed handlebar
2. Steering head components
• Improperly installed upper bracket
• Improperly installed lower bracket
(improperly tightened ring nut)
• Bent steering stem
• Damaged ball bearing or bearing race
3. Front fork leg (s)
• Uneven oil levels (both front fork legs)
• Unevenly tensioned fork spring (both front
fork legs)
• Broken fork spring
• Bent or damaged inner tube
• Bent or damaged outer tube
4. Swingarm
• Worn bearing or bushing
• Bent or damaged swingarm
5. Rear shock absorber assembly (-ies)
• Faulty rear shock absorber spring
• Leaking oil or gas
6. Tire (s)
• Uneven tire pressures (front and rear)
• Incorrect tire pressure
• Uneven tire wear
Summary of Contents for YZ 2018 Series
Page 6: ...EASB916006 YAMAHA MOTOR CORPORATION U S A YZ MOTORCYCLE LIMITED WARRANTY...
Page 10: ......
Page 40: ...MOTORCYCLE CARE AND STORAGE 1 28...
Page 64: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 23...
Page 66: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 25...
Page 68: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 27...
Page 70: ...CABLE ROUTING DIAGRAM 2 29 EASB29B065 CABLE ROUTING DIAGRAM...
Page 72: ...CABLE ROUTING DIAGRAM 2 31...
Page 74: ...CABLE ROUTING DIAGRAM 2 33...
Page 76: ...CABLE ROUTING DIAGRAM 2 35...
Page 78: ...CABLE ROUTING DIAGRAM 2 37...
Page 80: ...CABLE ROUTING DIAGRAM 2 39...
Page 82: ...CABLE ROUTING DIAGRAM 2 41...
Page 84: ...CABLE ROUTING DIAGRAM 2 43...
Page 255: ...OIL PUMP AND BALANCER GEAR 5 58 a 2 10 b 2 9 1 b 5 3 a 4 10 5 9 3 E c d 6 7 8 8 b 6...
Page 276: ...TRANSMISSION 5 79...
Page 290: ...FUEL TANK 7 5 A Left B Right 1 1 A 0 mm 0 in B 1 1 15 mm 0 59 in...
Page 296: ...THROTTLE BODY 7 11...
Page 299: ......
Page 313: ...CHARGING SYSTEM 8 14...
Page 321: ...COOLING SYSTEM For JPN 8 22...
Page 351: ...FUEL PUMP SYSTEM 8 52 EASB29B345...
Page 352: ...ELECTRICAL COMPONENTS 8 53 ELECTRICAL COMPONENTS EASB29B346 9 10 11 1 3 2 4 5 6 7 8...
Page 354: ...ELECTRICAL COMPONENTS 8 55 11 10 9 2 3 1 6 7 8 4 5...
Page 356: ...ELECTRICAL COMPONENTS 8 57 EASB29B347 CHECKING THE SWITCHES 4 1 3 2 B B Sb B B B B B B B B...
Page 372: ...ELECTRICAL COMPONENTS 8 73 c Measure the fuel injector resistance...