KTM 50 SX Repair Manual page 126

TROUBLESHOOTING
Faults
Engine does not speed up
Engine has too little power
Engine stalls or is popping into the
carburetor
Engine overheats
White smoke emission (steam in
exhaust gas)
Gear oil exits at the vent hose
Water in the gear oil
Possible cause
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
Ignition system defective
Diaphragm or reed valve housing
damaged
Noticeable wear
Clutch engagement speed too low or
too high
Lack of fuel
Engine takes in bad air
Socket connector or ignition coil is
loose or oxidized
Too little coolant in cooling system
Too little air stream
Radiator fins very dirty
Foam formation in cooling system
Damaged cylinder head or cylinder
head gasket
Bent radiator hose
Damaged cylinder head or cylinder
head gasket
Too much gear oil added
Damaged shaft seal ring or water
pump
Action
–
Check the ignition system. (
–
Check the fuel tank breather.
–
Clean the fuel tap.
(50 SX Junior, 50 SX Mini)
–
Check/set the carburetor components.
( p. 99)
(50 SX)
–
Check/set the carburetor components.
( p. 98)
–
Clean the air filter. ( p. 41)
–
Check exhaust system for damage.
–
Change the glass fiber yarn filling of the main
silencer.
–
Check the ignition coil. (
–
Check the spark plug connector. (
–
Check the diaphragm and reed valve housing.
–
Overhaul the engine.
–
Check the clutch engagement speed.
( p. 112)
–
Turn the knurled screw on the fuel tap all the
way counterclockwise.
–
Fill up with fuel.
–
Check the intake flange and carburetor for
tightness.
–
Clean the socket connector and treat it with
contact spray.
–
Check the cooling system for leakage.
–
Check the coolant level. (
–
Switch off engine when standing.
–
Clean radiator fins.
–
Drain the coolant. ( p. 114)
–
Refill the coolant. ( p. 114)
–
Check the cylinder head or cylinder head gas-
ket.
–
Change the radiator hose.
–
Check the cylinder head or cylinder head gas-
ket.
–
Check the gear oil level. (
–
Check the shaft seal ring and water pump.
124
p. 121)
p. 121)
p. 121)
p. 115)
p. 118)