KTM 125 SX EU 2015, Owner'S Manual

Page: 97 / 129

20 TROUBLESHOOTING
95
Faults Possible cause Action
The engine cannot be cranked (elec-
tric starter)
(All XC models) Operating error
–
Go through the steps of starting the engine.
( p. 23)
Battery discharged
–
Recharge the battery.
x
( p. 77)
–
Check the charging voltage.
x
–
Check the closed current.
x
–
Check the alternator.
x
Main fuse is blown
–
Remove the main fuse.
–
Install the main fuse.
Starter relay faulty
–
Check the starter relay. x
Starter motor faulty
–
Check the starter motor. x
Engine turns but does not start Operating error
–
Go through the steps of starting the engine.
( p. 23)
Motorcycle was out of use for a long
time and there is old fuel in the float
chamber
–
Empty the carburetor float chamber.
x
( p. 85)
Fuel feed interrupted
–
Check the fuel tank breather.
–
Clean the fuel tap.
–
Check/set the carburetor components.
Spark plug oily or wet
–
Clean and dry the spark plug, or change it if
necessary.
Electrode distance (plug gap) of spark
plug too wide
–
Adjust the plug gap.
Guideline
(125/150 SX)
Spark plug electrode gap
0.60 mm (0.0236 in)
(All 250/300 models)
Spark plug electrode gap
0.60 mm (0.0236 in)
Fault in ignition system
–
Check the ignition system.
x
Kill switch cable in wiring harness
frayed, kill switch defective
–
Check the kill switch.
x
The connector or ignition coil is loose
or oxidized
–
Clean the connector and treat it with contact
spray.
Water in carburetor or jets blocked
–
Check/set the carburetor components.
Engine has no idle Idling jet blocked
–
Check/set the carburetor components.
Adjusting screws on carburetor dis-
torted
–
Carburetor - adjust the idle speed. x
( p. 84)
Spark plug defective
–
Change the spark plug.
Ignition system defective
–
Check the ignition coil. x
–
Check the spark plug connector.
x
Engine does not speed up Carburetor running over because float
needle dirty or worn
–
Check/set the carburetor components.
Loose carburetor jets
–
Check/set the carburetor components.
Fault in ignition system
–
Check the ignition system.
x
Engine has too little power Fuel feed interrupted
–
Check the fuel tank breather.
–
Clean the fuel tap.
–
Check/set the carburetor components.
Air filter very dirty
–
Clean the air filter and air filter box.
x
( p. 49)
Exhaust system leaky, deformed or
too little glass fiber yarn filling in
main silencer
–
Check exhaust system for damage.
–
Change the glass fiber yarn filling of the main
silencer.
x
( p. 51)
Fault in ignition system
–
Check the ignition system.
x
Diaphragm or reed valve housing
damaged
–
Check the diaphragm and reed valve housing.