Troubleshooting - KTM 125 SX Owner's Manual

20

TROUBLESHOOTING

Faults
The engine cannot be cranked (elec-
tric starter)
(All XC models)
Engine turns but does not start
Engine has no idle
Engine does not speed up
Engine has too little power
Possible cause
Operating error
Battery discharged
Main fuse is blown
Starter relay faulty
Starter motor faulty
Operating error
Motorcycle was out of use for a long
time and there is old fuel in the float
chamber
Fuel feed interrupted
Spark plug oily or wet
Electrode distance (plug gap) of spark
plug too wide
Fault in ignition system
Kill switch cable in wiring harness
frayed, kill switch defective
The connector or ignition coil is loose
or oxidized
Water in carburetor or jets blocked
Idling jet blocked
Adjusting screws on carburetor dis-
torted
Spark plug defective
Ignition system defective
Carburetor running over because float
needle dirty or worn
Loose carburetor jets
Fault in ignition system
Fuel feed interrupted
Air filter very dirty
Exhaust system leaky, deformed or
too little glass fiber yarn filling in
main silencer
Fault in ignition system
Diaphragm or reed valve housing
damaged
Action
–
Carry out the start procedure. (
–
Recharge the battery.
–
Check the charging voltage.
–
Check the closed current.
–
Check the alternator.
–
Remove the main fuse.
–
Install the main fuse.
–
Check the starter relay.
–
Check the starter motor.
–
Carry out the start procedure. (
–
Empty the carburetor float chamber.
( p. 103)
–
Check the fuel tank breather.
–
Clean the fuel tap.
–
Check/set the carburetor components.
–
Clean and dry the spark plug, or change it if
necessary.
–
Adjust the plug gap.
Guideline
(All 125/150 models)
Spark plug electrode gap
0.60 mm (0.0236 in)
(All 250/300 models)
Spark plug electrode gap
0.60 mm (0.0236 in)
–
Check the ignition system.
–
Check the kill switch.
–
Clean the connector and treat it with contact
spray.
–
Check/set the carburetor components.
–
Check/set the carburetor components.
– Carburetor – adjust the idle speed.
( p. 98)
–
Change the spark plug.
–
Check the ignition coil.
–
Check the spark plug connector.
–
Check/set the carburetor components.
–
Check/set the carburetor components.
–
Check the ignition system.
–
Check the fuel tank breather.
–
Clean the fuel tap.
–
Check/set the carburetor components.
–
Clean the air filter and air filter box.
( p. 59)
–
Check exhaust system for damage.
–
Change glass fiber yarn filling in the main
silencer. ( p. 62)
–
Check the ignition system.
–
Check the diaphragm and reed valve housing.
109
p. 23)
( p. 90)
p. 23)