Poor Medium-And-High-Speed Performance; Faulty Drive Train; Faulty Gear Shifting; Shift Lever Does Not Move - Yamaha Grizzly550 User Manual

Electrical system
1. Battery
• Discharged battery
• Faulty battery
2. Spark plug
• 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
• 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
EAS30320

FAULTY DRIVE TRAIN

The following conditions may indicate damaged shaft drive components:
Symptoms
1. A pronounced hesitation or "jerky" movement
during acceleration, deceleration, or sus-
tained speed. (This must not be confused
with engine surging or transmission charac-
teristics.)
2. A "rolling rumble" noticeable at low speed; a
high-pitched whine; a "clunk" from a shaft
drive component or area.
3. A locked-up condition of the shaft drive
mechanism, no power transmitted from the
engine to the front and/or rear wheels.
TIP
Areas A, B, and C above may be extremely difficult to diagnose. The symptoms are quite subtle and
difficult to distinguish from normal vehicle operating noise. If there is reason to believe these compo-
nents are damaged, remove the components and check them.
EAS28530

FAULTY GEAR SHIFTING

Shifting is difficult
Refer to "FAULTY CLUTCH" on page 10-3.
EAS3B41028

SHIFT LEVER DOES NOT MOVE

Shift drum and shift forks
• Foreign object in a shift drum groove
• Seized shift fork
• Bent shift fork guide bar
TROUBLESHOOTING
• Broken AC magneto rotor woodruff key
5. Valve train
• Improperly adjusted valve clearance
• Improperly adjusted valve timing
EAS28510
POOR MEDIUM-AND-HIGH-SPEED
PERFORMANCE
Refer to "STARTING FAILURES" on page 10-1.
Engine
1. Air filter
• Clogged air filter element
Fuel system
1. Fuel pump
• Faulty fuel pump
Possible Causes
A. Bearing damage.
B. Improper gear backlash.
C. Gear tooth damage.
D. Broken drive shaft.
E. Broken gear teeth.
F. Seizure due to lack of lubrication.
G. Small foreign objects lodged between the
moving parts.
Transmission
• Seized transmission gear
• Foreign object between transmission gears
• Improperly assembled transmission
EAS28550

JUMPS OUT OF GEAR

Shift forks
• Worn shift fork
Shift drum
• Incorrect axial play
• Worn shift drum groove
10-2
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