Poor Medium-And-High-Speed Performance; Faulty Gear Shifting; Shift Pedal Does Not Move; Jumps Out Of Gear - Yamaha XT250X Service Manual

Incorrect valve clearance
G
Damaged valve train components
G
2. Air filter
Clogged air filter element
G
Fuel system
1. Carburetor(s)
Faulty starter plunger
G
Loose or clogged pilot jet
G
Loose or clogged pilot air jet
G
Damaged or loose carburetor joint
G
Improperly synchronized carburetors
G
Improperly adjusted engine idling speed
G
(throttle stop screw)
Improper throttle cable free play
G
Flooded carburetor
G
Faulty air induction system
G
Electrical system
1. Battery
Discharged battery
G
Faulty battery
G
2. Spark plug(s)
Incorrect spark plug gap
G
Incorrect spark plug heat range
G
Fouled spark plug
G
Worn or damaged electrode
G
Worn or damaged insulator
G
Faulty spark plug cap
G
3. Ignition coil(s)
Broken or shorted primary or secondary coils
G
Faulty spark plug lead
G
Cracked or broken ignition coil
G
4. Ignition system
Faulty ignitor unit
G
Faulty pickup coil
G
Broken generator rotor woodruff key
G
EAS28520
POOR MEDIUM-AND-HIGH-SPEED
PERFORMANCE
Refer to "STARTING FAILURES" on page 8-1.
Engine
1. Air filter
Clogged air filter element
G
2. Air intake system
Bent, clogged or disconnected carburetor air
G
vent hose
Clogged or leaking air duct
G
Fuel system
1. Carburetor(s)
Faulty diaphragm
G
Incorrect fuel level
G
Loose or clogged main jet
G
2. Fuel pump
Faulty fuel pump
G
TROUBLESHOOTING
EAS28530

FAULTY GEAR SHIFTING

Shifting is difficult
Refer to "Clutch drags".
EAS28540

SHIFT PEDAL DOES NOT MOVE

Shift shaft
Improperly adjusted shift rod
G
Bent shift shaft
G
Shift drum and shift forks
Foreign object in a shift drum groove
G
Seized shift fork
G
Bent shift fork guide bar
G
Transmission
Seized transmission gear
G
Foreign object between transmission gears
G
Improperly assembled transmission
G
EAS28550

JUMPS OUT OF GEAR

Shift shaft
Incorrect shift pedal position
G
Improperly returned stopper lever
G
Shift forks
Worn shift fork
G
Shift drum
Incorrect axial play
G
Worn shift drum groove
G
Transmission
Worn gear dog
G
EAS28560

FAULTY CLUTCH

Clutch slips
1. Clutch
Improperly assembled clutch
G
Improperly adjusted clutch cable
G
Loose or fatigued clutch spring
G
Worn friction plate
G
Worn clutch plate
G
2. Engine oil
Incorrect oil level
G
Incorrect oil viscosity (low)
G
Deteriorated oil
G
Clutch drags
1. Clutch
Unevenly tensioned clutch springs
G
Warped pressure plate
G
Bent clutch plate
G
Swollen friction plate
G
Bent clutch push rod
G
Broken clutch boss
G
Burnt primary driven gear bushing
G
Match marks not aligned
G
2. Engine oil
8-2