Yamaha XV19SW(C), XV19W(C), XV19MW(C), XV19CTSW(C), XV19CTW(C), XV19CTMW(C). Service Manual - part 28

8

TROUBLESHOOTING

TROUBLESHOOTING

.................................................................................... 8-1

GENERAL INFORMATION ....................................................................... 8-1
STARTING FAILURES ............................................................................. 8-1
INCORRECT ENGINE IDLING SPEED .................................................... 8-1
POOR MEDIUM AND HIGH-SPEED PERFORMANCE ........................... 8-2
FAULTY GEAR SHIFTING ....................................................................... 8-2
SHIFT PEDAL DOES NOT MOVE............................................................ 8-2
JUMPS OUT OF GEAR ............................................................................ 8-2
FAULTY CLUTCH ..................................................................................... 8-2
OVERHEATING ........................................................................................ 8-3
POOR BRAKING PERFORMANCE.......................................................... 8-3
FAULTY FRONT FORK LEGS.................................................................. 8-3
UNSTABLE HANDLING............................................................................ 8-3
FAULTY LIGHTING OR SIGNALING SYSTEM........................................ 8-4

TROUBLESHOOTING

8-1

EAS28450

TROUBLESHOOTING

EAS28460

GENERAL INFORMATION

NOTE:

The following guide for troubleshooting does not 
cover all the possible causes of trouble. It should 
be helpful, however, as a guide to basic trouble-
shooting. Refer to the relative procedure in this 
manual for checks, adjustments, and replace-
ment of parts.

EAS28470

STARTING FAILURES

Engine

1. Cylinder(s) and cylinder head(s)

• Loose spark plug
• Loose cylinder head or cylinder
• Damaged cylinder head gasket
• Damaged cylinder gasket
• Worn or damaged cylinder
• Incorrect valve clearance
• Improperly sealed valve
• Incorrect valve-to-valve-seat contact
• Incorrect valve timing
• Faulty valve spring
• Seized valve

2. Piston(s) and piston ring(s)

• Improperly installed piston ring
• Damaged, worn or fatigued piston ring
• Seized piston ring
• Seized or damaged piston

3. Air filter

• Improperly installed air filter
• Clogged air filter element

4. Crankcase and crankshaft

• Improperly assembled crankcase
• Seized crankshaft

Fuel system

1. Fuel tank

• Empty fuel tank
• Clogged fuel filter
• Clogged fuel tank overflow/breather hose
• Clogged rollover valve
• Clogged rollover valve hose
• Deteriorated or contaminated fuel

2. Fuel pump

• Faulty fuel pump
• Faulty relay unit (fuel pump relay)

3. Throttle body(-ies)

• Deteriorated or contaminated fuel

• Sucked-in air

Electrical system

1. Battery

• Discharged battery
• Faulty battery

2. Fuse(s)

• Blown, damaged or incorrect fuse
• Improperly installed fuse

3. Spark plug(s)

• Incorrect spark plug gap
• Incorrect spark plug heat range
• Fouled spark plug
• Worn or damaged electrode
• Worn or damaged insulator
• Faulty spark plug cap

4. Ignition coil(s)

• Cracked or broken ignition coil body
• Broken or shorted primary or secondary coils
• Faulty spark plug lead

5. Ignition system

• Faulty ECU
• Faulty crankshaft position sensor
• Broken generator rotor woodruff key

6. Switches and wiring

• Faulty main switch
• Faulty engine stop switch
• Broken or shorted wiring
• Faulty neutral switch
• Faulty start switch
• Faulty sidestand switch
• Faulty clutch switch
• Improperly grounded circuit
• Loose connections

7. Starting system

• Faulty starter motor
• Faulty starter relay
• Faulty relay unit (starting circuit cut-off relay)
• Faulty starter clutch

EAS28490

INCORRECT ENGINE IDLING SPEED

Engine

1. Cylinder(s) and cylinder head(s)

• Incorrect valve clearance
• Damaged valve train components

2. Air filter

• Clogged air filter element

Fuel system

1. Throttle body(-ies)

• Damaged or loose throttle body joint
• Improperly synchronized throttle bodies

TROUBLESHOOTING

8-2

• Improper throttle cable free play
• Flooded throttle body

Electrical system

1. Battery

• Discharged battery
• Faulty battery

2. Spark plug(s)

• Incorrect spark plug gap
• Incorrect spark plug heat range
• Fouled spark plug
• Worn or damaged electrode
• Worn or damaged insulator
• Faulty spark plug cap

3. Ignition coil(s)

• Broken or shorted primary or secondary coils
• Faulty spark plug lead
• Cracked or broken ignition coil

4. Ignition system

• Faulty ECU
• Faulty crankshaft position sensor
• Broken generator rotor woodruff key

EAS28510

POOR MEDIUM AND HIGH-SPEED 
PERFORMANCE

Refer to “STARTING FAILURES” on page 8-1.

Engine

1. Air filter

• Clogged air filter element

Fuel system

1. Fuel pump

• Faulty fuel pump

EAS28530

FAULTY GEAR SHIFTING

Shifting is difficult

Refer to “Clutch drags”.

EAS28540

SHIFT PEDAL DOES NOT MOVE

Shift shaft

• Improperly adjusted shift rod
• Bent shift shaft

Shift drum and shift forks

• Foreign object in a shift drum groove
• Seized shift fork
• Bent shift fork guide bar

Transmission

• Seized transmission gear
• Foreign object between transmission gears
• Improperly assembled transmission

EAS28550

JUMPS OUT OF GEAR

Shift shaft

• Incorrect shift pedal position
• Improperly returned stopper lever

Shift forks

• Worn shift fork

Shift drum

• Incorrect axial play
• Worn shift drum groove

Transmission

• Worn gear dog

EAS28570

FAULTY CLUTCH

Clutch slips

1. Clutch

• Improperly assembled clutch
• Improperly assembled clutch master cylinder
• Improperly assembled clutch release cylinder
• Incorrect clutch fluid level
• Damaged clutch hose
• Loose or fatigued clutch spring
• Loose union bolt
• Worn friction plate
• Worn clutch plate
• Damaged clutch release cylinder

2. Engine oil

• Incorrect oil level
• Incorrect oil viscosity (low)
• Deteriorated oil

Clutch drags

1. Clutch

• Air in hydraulic clutch system
• Unevenly tensioned clutch springs
• Warped pressure plate
• Bent clutch plate
• Swollen friction plate
• Bent clutch push rod
• Damaged clutch boss
• Burnt primary driven gear bushing
• Damaged clutch release cylinder
• Match marks not aligned

TROUBLESHOOTING

8-3

2. Engine oil

• Incorrect oil level
• Incorrect oil viscosity (high)
• Deteriorated oil

EAS28590

OVERHEATING

Engine

1. Cylinder head(s) and piston(s)

• Heavy carbon buildup

2. Engine oil

• Incorrect oil level
• Incorrect oil viscosity
• Inferior oil quality

Fuel system

1. Throttle body(-ies)

• Faulty throttle body(-ies)
• Damaged or loose throttle body joint

2. Air filter

• Clogged air filter element

Chassis

1. Brake(s)

• Dragging brake

Electrical system

1. Spark plug(s)

• Incorrect spark plug gap
• Incorrect spark plug heat range

2. Ignition system

• Faulty ECU

EAS28620

POOR BRAKING PERFORMANCE

• Worn brake pad
• Worn brake disc
• Air in hydraulic brake system
• Leaking brake fluid
• 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

EAS28660

FAULTY FRONT FORK LEGS

Leaking oil

• 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

Malfunction

• Bent or damaged inner tube
• Bent or damaged outer tube
• Damaged fork spring
• Worn or damaged outer tube bushing
• Bent or damaged damper rod
• Incorrect oil viscosity
• Incorrect oil level

EAS28670

UNSTABLE HANDLING

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

• 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
• Deformed cast wheel
• Damaged wheel bearing
• Bent or loose wheel axle
• Excessive wheel runout

8. Frame

• Bent frame
• Damaged steering head pipe
• Improperly installed bearing race

TROUBLESHOOTING

8-4

EAS28710

FAULTY LIGHTING OR SIGNALING SYSTEM

Headlight does not come on

• Wrong headlight bulb
• Too many electrical accessories
• Hard charging
• Incorrect connection
• Improperly grounded circuit
• Poor contacts (main switch)
• Burnt-out headlight bulb

Headlight bulb burnt out

• Wrong headlight bulb
• Faulty battery
• Faulty rectifier/regulator
• Improperly grounded circuit
• Faulty main switch
• Headlight bulb life expired

Tail/brake light does not come on

• Wrong tail/brake light LED
• Too many electrical accessories
• Incorrect connection
• Burnt-out tail/brake light LED

Tail/brake light LED burnt out

• Wrong tail/brake light LED
• Faulty battery
• Incorrectly adjusted rear brake light switch
• Tail/brake light LED life expired

Turn signal does not come on

• Faulty turn signal switch
• Faulty turn signal relay
• Burnt-out turn signal bulb
• Incorrect connection
• Damaged or faulty wire harness
• Improperly grounded circuit
• Faulty battery
• Blown, damaged or incorrect fuse

Turn signal flashes slowly

• Faulty turn signal relay
• Faulty main switch
• Faulty turn signal switch
• Incorrect turn signal bulb

Turn signal remains lit

• Faulty turn signal relay
• Burnt-out turn signal bulb

Turn signal flashes quickly

• Incorrect turn signal bulb

• Faulty turn signal relay
• Burnt-out turn signal bulb

Horn does not sound

• Improperly adjusted horn
• Damaged or faulty horn
• Faulty main switch
• Faulty horn switch
• Faulty battery
• Blown, damaged or incorrect fuse
• Faulty wire harness

XV19SW(C)/XV19W(C)/XV19MW(C)/XV19CTSW(C)/XV19CTW(C)/XV19CTMW(C) 2007 WIRING DIAGRAM

(GRAY)

(BLUE)

(BLUE)

(BLACK)

(BLACK)

(BLACK)

(BLACK)

(BLACK)

(GRAY)

(GRAY)

(GRAY)

(GRAY)

(GRAY)

(BLUE)

(BLUE)

(GRAY)

(BLACK)

(BLACK)

(BLACK) (BLACK)

(BLACK)

(BLACK)

(BLACK)

(GRAY)

(DARK GRAY)

(BLACK)

(BLACK)

(BLACK)

(BLACK)

(BLACK)

(GRAY)

(GRAY)

(BLACK)

(BLACK)

(BLACK)

(BLACK)

(GRAY)

(GRAY)

ON

OFF

D
D

C

C

D

D

C

D

D

E

E

E

B

B

B
B

B

B

(L)

N

(R)

PUSH

A

A

(BLACK)

A

A

A

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

32

32

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

81

80

A

WIRE HARNESS

WIRE HARNESS

WIRE HARNESS

WIRE HARNESS  SUB WIRE HARNESS2

E

WIRE HARNESS

 SUB WIRE HARNESS1

 SUB WIRE HARNESS2

 SUB WIRE HARNESS4

 SUB WIRE HARNESS3

B

C

D

(BLACK)

(BLACK)

(BLACK)

(BLACK)

EAS28740

WIRING DIAGRAM

XV19SW(C)/XV19W(C)/
XV19MW(C)/XV19CTSW(C)/
XV19CTW(C)/XV19CTMW(C) 
2007

1. AC magneto
2. Rectifier/regulator
3. Main switch
4. Main fuse
5. Backup fuse (odometer and 

clock)

6. Battery
7. Fuel injection system fuse
8. Starter relay
9. Starter motor
10. Diode 1
11. Relay unit
12. Starting circuit cut-off relay
13. Fuel pump relay
14. Neutral switch
15. Diode 2
16. Sidestand switch
17. Fuel pump
18. Fuel sender (fuel pump)
19. Crankshaft position sensor
20. Throttle position sensor
21. Cylinder-#1 intake air pressure 

sensor

22. Cylinder-#2 intake air pressure 

sensor

23. Lean angle sensor
24. Speed sensor
25. Air temperature sensor
26. Engine temperature sensor
27. ECU (electronic control unit)
28. Cylinder-#1 left ignition coil
29. Cylinder-#1 right ignition coil
30. Cylinder-#2 left ignition coil
31. Cylinder-#2 right ignition coil
32. Spark plug
33. ISC (idle speed control) unit
34. EXUP servo motor
35. Injector #1
36. Injector #2
37. O

2

 sensor

38. Meter assembly
39. Neutral indicator light
40. Multi-function meter
41. Reset switch
42. Engine trouble warning light
43. Fuel level warning light
44. Meter light
45. Left turn signal indicator light
46. Right turn signal indicator light
47. High beam indicator light
48. Fuel sender (fuel tank)
49. Horn 1
50. Horn 2
51. Turn signal relay

52. Headlight relay
53. Left handlebar switch
54. Clutch switch
55. Dimmer switch
56. Turn signal switch
57. Horn switch
58. Select switch
59. Front right turn signal/position 

light

60. Front left turn signal/position 

light

61. Rear right turn signal light
62. Rear left turn signal light
63. Headlight assembly
64. Headlight (high beam)
65. Headlight (low beam)
66. Right handlebar switch
67. Front brake light switch
68. Engine stop switch
69. Start switch
70. Accessory light switch
71. Accessory light (OPTION)
72. Tail/brake light
73. License plate light
74. Rear brake light switch
75. Auxiliary DC coupler
76. Auxiliary DC connector fuse
77. Ignition fuse
78. Headlight fuse
79. Signaling system fuse
80. Taillight fuse
81. ECU fuse

EAS28750

COLOR CODE

B

Black

Br

Brown

Ch

Chocolate

Dg

Dark green

G

Green

Gy

Gray

L

Blue

O

Orange

P

Pink

R

Red

Sb

Sky blue

W

White

Y

Yellow

B/Br

Black/Brown

B/G

Black/Green

B/L

Black/Blue

B/R

Black/Red

B/Y

Black/Yellow

Br/L

Brown/Blue

Br/W

Brown/White

G/L

Green/Blue

G/R

Green/Red

G/W

Green/White

G/Y

Green/Yellow

Gy/G

Gray/Green

Gy/R

Gray/Red

Gy/W

Gray/White

L/B

Blue/Black

L/G

Blue/Green

L/R

Blue/Red

L/W

Blue/White

L/Y

Blue/Yellow

P/L

Pink/Blue

P/W

Pink/White

P/Y

Pink/Yellow

R/B

Red/Black

R/G

Red/Green

R/L

Red/Blue

R/W

Red/White

R/Y

Red/Yellow

Sb/W

Sky blue/White

W/B

White/Black

W/G

White/Green

W/R

White/Red

W/Y

White/Yellow

Y/B

Yellow/Black

Y/G

Yellow/Green

Y/L

Yellow/Blue

Y/R

Yellow/Red