Trouble Shooting - KTM 400 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 nevertheless, 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
32
Engine will not idle
Engine does not rev high
Engine will not reach full
power

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 genera-
tor 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 carburetor or jets blocked
Carburetor does not fit in properly
at intake flange
Idling jet blocked
Adjusting screws on carburetor
uncorrect adjusted
Ignition system faulty
Carburetor fuel level too high
because float needle valve is dirty
or worn out
Loose carburetor jets
Electronical ignition timing faulty
Fuel supply partically interrupted or
carburetor dirty
float is not tight, or no axial play
Air filter very dirty
Exhaust leaking or blocked
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 carburetor
– if no fuel leaks out, check tank ventilation, i.e. clean fuel tap
See driving instructions
Clean or replace spark plug
Adjust spark plug electrode 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 produced 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 black/yellow cable from 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 carburetor
Check if carburetor is fitted in correctly
Dismount carburetor and clean jets
Adjust carburettor
Have ignition system checked
Dismount carburetor and check if worn out
Tighten jets
Have ignition system checked
Clean and check fuel system as well as carburetor
replace or abrade the float
Clean or replace air filter
Check if exhaust is damaged, replace glas fibre yarn in exhaust
silencer