Trouble Shooting - KTM 400 SX Owner's Handbook Manual

If you let the specified maintenance work on your motorcycle be carried out, disturbances can hardly be expected. Should an error occur nevert-
heless, we advise you to use the trouble shooting chart in order to find the cause of error.
We would like to point out that many operations cannot be performed by oneself. In case of uncertainty, please contact a KTM-dealer.
TROUBLE
Engine will not start
36
Engine will not idle
Engine does not rev high

TROUBLE SHOOTING

CAUSE
Operating error
Fuel supply interrupted
Flooded engine
Sooty or wet spark plug
Electrode gap too large
Spark plug connector or spark plug
faulty
If connector oxidates from generator to
ignition coil
Short circuit cable scored in wiring
harness, ignition lock, emergency OFF
switch or short circuit button faulty
Water in short emergency OFF switch
Water in carburettor or jets blocked
Carburettor does not fit in properly at
intake flange
Idling jet blocked
Adjusting screws on carburettor uncor-
rect adjusted
Ignition system faulty
Carburettor fuel level too high because
float needle valve is dirty or worn out
Loose carburettor jets
Electronical ignition timing faulty
REMEDY
Switch on ignition, switch on emergency OFF switch, open fuel tap,
tank fuel, do not use choke i.e. the hotstart device. Pay attention to
starting off information (see driving instructions).
Close fuel tap, loosen fuel hose at carburettor, lead into a basin and
open fuel tap,
– if fuel leaks out, clean carburettor
– if no fuel leaks out, check tank ventilation, i.e. clean fuel tap
See driving instructions
Clean or replace spark plug
Adjust spark plug elektrode gap to 0,6 mm
Dismount spark plug, connect ignition cable, hold to ground (blank
place on engine) and actuate kickstarter, a strong spark must be pro-
duced at the spark plug
– If no spark is produced, loosen spark plug cap from ignition cable,
hold about 5 mm from ground and actuate kickstarter
– If a spark now occurs, replace spark plug cap
– If no spark is produced, control ignition system
Remove fuel tank, clean connector and treat with contact spray
Remove fuel tank, draw off blue/black cable from orange cable of
ignition coil and check spark.
– If a spark is produced, seek fault in short circuit current
Remove 2-pole connector located underneath the headlight mask,
treat emergency OFF switch with contact spray
Dismount and clean carburettor
Check if carburettor is fitted in correctly
Dismount carburettor and clean jets
Adjust carburettor
Have ignition system checked
Dismount carburettor and check if worn out
Tighten jets
Have ignition system checked