KTM 250 SX - Manual (Page 82)

8-3C
TROUBLE
Engine has not enough
power
Engine revs not high and
running with four stroke
cycle
High rpm misfiring
Engine spluters into the
carburetor
Engine overheating
Emission of white smoke
(steam)
Excessive oil escapes from
transmission breather tube
All switched on lamps
blown out
CAUSE
Reed paddles tensionless or dama-
ged, surface of reed valve housing
damaged
Wear
Electronical ignition timing faulty
Carburetor overflows if level adjust
too high, float needle seating is
dirty or enlarged
Loose carburetor jets
Incorrect heat range spark plug or
low quality spark plug
Incorrect or faulty spark plug connector
Loose, corroded or non conductive
ignition socket connector
Lack of fuel
Spark plug with incorrect heat value
(Ignition by incandescence)
Engine takes air out of control
Insufficient liquid in cooling system
Cooling system not or insufficiently
bleeded
Radiator fins clogged
Frothing in cooling system
Pinched or kinked water hoses
Incorrect ignition timing because of
loose stator bolts
Incorrect dimension ,,X“
Cylinder head or O-ring of cylinder
head gasket leaks
Excessive oil quantity in trans-
mission
Water pump shaft seal ring or right-
hand crankshaft seal ring defect
Silicon O-rings of control roller or of
control flap leaks
Voltage regulator faulty
REMEDY
Replace reed paddles or reed valve housing
Overhaul engine
Check ignition system
Clean carburetor, if necessary replace float needle and adjust
level
Tighten jets
Refer to technical data section
Test and/or replace spark plug connectors correct type
Check and seal with silicon
Clean fuel pipes, examine tank aeration and clean
Fit correct spark plug
Check intake flange and carburettor if firmly setted
Top up coolant and bleed cooling system check cooling system
for leaks
Bleed cooling system (see operating instructions)
Clean radiator fins with water jet
Renew coolant using branded anti-freeze/anti-corrosive
Replace with correct routed hoses
Readjust to correct ignition timing specifications, secure
screws properly with Loctite 243
Measure and adjust to correct specification
Check cylinder head, replace O-ring
Correct transmission oil level
Replace shaft seal ring and change gear oil, check coolant
Replace O-rings
Control connections of voltage regulator. Check voltage
regulator