KTM 450 SX-F Repair Manual page 115

TROUBLE
Engine doesn't crank (E-starter). Blown fuse
Engine cranks but doesn't start
(E-starter).
Engine fails to idle
CAUSE
Discharged battery
Low outside temperature
Operating error
The motorcycle has been out of
operation for a longer period of time.
Therefore old fuel has accumulated in
the float chamber
Fuel supply interrupted
Flooded engine
Sooty or wet spark plug
Electrode gap too large
Spark plug connector or spark plug
faulty
Short circuit cable scored in wiring
harness, short circuit button faulty
The plug connection of the CDI-unit,
the pulse generator or the ignition coil
has oxydized
Water in carburetor or jets blocked
Clogged idling jet
Incorrect adjustment of adjusting
screws on carburetor
Defective spark plug
Defective ignition system
REMEDY
Dismount the filter box cover and replace the fuse in the
starter relay.
Recharge the battery and investigate the causes for
discharging.
Use the 12 V / 4 Ah battery included in the scope of
supply.
Open fuel tap, tank fuel, actuate choke. Pay attention
to starting information (see driving instructions).
The easily inflammable components of the new fuels
evaporate during longer periods of standing still.
When the motorcycle has been out of operation for more
than a week, it is therefore recommended to drain the
old fuel from the float chamber. The engine will
immediately start when the float chamber is filled with
new fuel.
Close fuel tap, loosen fuel hose at carburetor, lead into
a basin and open fuel tap
– if fuel leaks out, the carburetor may need cleaning
– if no fuel leaks out, check tank ventilation, i.e. clean
fuel tap
Clean and dry the spark plug or exchange it, respectively
Clean and dry the spark plug or exchange it, respectively
Adjust spark plug electrode gap to 0.6 mm
Dismount spark plug, connect ignition cable, hold to
ground (blank place on engine) and actuate starter, a strong
spark must be produced at the spark plug
– If no spark is created replace the spark plug.
– If the new spark plug doesn't produce a spark either,
disconnect the spark plug connector from the ignition
cable, hold it a distance of approx. 5 mm from ground
and start.
– If a spark now occurs, replace spark plug cap
– If no spark is produced, control ignition system
Dismount the fuel tank, disconnect the black/yellow
cable from the cable of the short-circuit button,
respectively, and check the ignition spark.
If a spark is generated, look for the problem in the short-
circuit circuit.
Remove the seat and the fuel tank. Clean the plug
connection and treat it with contact spray
Dismount and clean the carburetor
Disassemble the carburetor and clean the jets
Adjust carburetor
Replace the spark plug
Check ignition system
9-2