TROUBLESHOOTING
9-3
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
EASB291380
OVERCOOLING
Cooling system
1. Coolant temperature sensor
• Faulty coolant temperature sensor
EASB291381
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
EASB291382
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
EASB291383
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
EASB291384
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
7. Wheel (s)
• Incorrect wheel balance
• Broken or loose spoke
• Damaged wheel bearing
• Bent or loose wheel axle
• Excessive wheel runout
8. Frame
• Bent frame
• Damaged steering head pipe
• Improperly installed bearing race
Summary of Contents for YZ 2015 Series
Page 6: ...EASB291006 YAMAHA MOTOR CORPORATION U S A YZ MOTORCYCLE LIMITED WARRANTY...
Page 10: ......
Page 33: ...CONTROL FUNCTIONS 1 21 a 2...
Page 65: ...LUBRICATION POINTS AND LUBRICANT TYPES 2 22 EASB291066...
Page 68: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 25...
Page 70: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 27...
Page 72: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 29...
Page 74: ...CABLE ROUTING DIAGRAM 2 31 EASB291068 CABLE ROUTING DIAGRAM...
Page 76: ...CABLE ROUTING DIAGRAM 2 33...
Page 78: ...CABLE ROUTING DIAGRAM 2 35...
Page 80: ...CABLE ROUTING DIAGRAM 2 37...
Page 82: ...CABLE ROUTING DIAGRAM 2 39...
Page 84: ...CABLE ROUTING DIAGRAM 2 41...
Page 86: ...CABLE ROUTING DIAGRAM 2 43...
Page 88: ...CABLE ROUTING DIAGRAM 2 45...
Page 128: ...ELECTRICAL SYSTEM 3 38...
Page 200: ...CHAIN DRIVE 4 70...
Page 244: ...ELECTRIC STARTER 5 41...
Page 266: ...OIL PUMP AND BALANCER GEAR 5 63 c d 6 6 7 8 8 b...
Page 286: ...TRANSMISSION 5 83...
Page 306: ...CHECKING THE INTAKE AIR TEMPERATURE SENSOR 8 67 CHECKING THE FUEL INJECTOR 8 68...
Page 321: ...CHARGING SYSTEM 8 15 EASB291338...
Page 325: ...COOLING SYSTEM For JPN 8 19 EASB291341...
Page 355: ...FUEL PUMP SYSTEM 8 49 EASB291348...
Page 356: ...ELECTRICAL COMPONENTS 8 50 ELECTRICAL COMPONENTS EASB291349 8 9 10 1 3 2 4 5 6 7...
Page 358: ...ELECTRICAL COMPONENTS 8 52 11 10 9 2 3 1 6 7 8 4 5...
Page 360: ...ELECTRICAL COMPONENTS 8 54 EASB291350 CHECKING THE SWITCHES 4 1 3 2 E B S E B E B E E B B...
Page 382: ...LIST OF SELF DIAGNOSTIC AND FAIL SAFE ACTIONS 9 7...