Troubleshooting; General Information; Starting Failures; Incorrect Engine Idling Speed - Yamaha Vmax VMX17C 2009 Service Manual

EAS28451

TROUBLESHOOTING

EAS28460

GENERAL INFORMATION

TIP
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
• Damaged cylinder head 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 overflow hose
• Clogged rollover valve
• Clogged fuel tank breather hose
• Deteriorated or contaminated fuel
2. Fuel pump
• Faulty fuel pump
• Faulty fuel pump relay
3. Throttle body(-ies)
• Deteriorated or contaminated fuel
• Sucked-in air
TROUBLESHOOTING
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
4. Ignition coil(s)
• Cracked or broken ignition coil body
• Broken or shorted primary or secondary coils
5. Ignition system
• Faulty ECU
• Faulty crankshaft position sensor
• Faulty cylinder identification sensor
• Broken generator rotor woodruff key
6. Switches and wiring
• Faulty main switch
• Faulty engine stop switch
• Broken or shorted wiring
• Faulty gear position 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 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
• Improper throttle cable free play
• Flooded throttle body
• Faulty air induction system
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