Trouble Shooting - KTM 50 SX PRO JUNIOR LC Owner's 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 fails to start
28
Engine without idle run-
ning
Less power of engine

TROUBLE SHOOTING

CAUSE
Operating error
Fuel supply interrupted
Electrode distance too large
Plug fouled by oil, wet or bridged
Ignition wire or spark
connector damaged
Kill button wire or
short-circuit switch faulty
Loose ignition cable connectors
Spark too weak
Water in the carburetor and jets
blocked
Idle adjusting screw out of adjust-
ment
Ignition system damaged
Wear
Air filter obstructed
Fuel supply partly interrupted or
blocked
Loss of compression due to loose
spark plug
Exhaust system damaged
Engine has not enough preignition
Reed paddles tensionless or dama-
ged, surface of reed valve housing
damaged
Wear
Open fuel tap, replenish fuel, do not use choke
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
Reduce electrode distance (0.60 mm)
Clean spark plug or renew
plug 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
Disconnect black coloured cable from short circuit button at
ignition coil and check ignition spark. If the spark is O.K. repair
defective part of cable or ignition switch
Inspect cable connectors
Examine ignition system
Dismantle and clean carburetor
Readjust idle running or replace idle adjusting screw
Examine ignition system
Overhaul engine
Clean or renew airfilter
Blow through fuel pipe and clean carburetor
Tighten spark plug
Check exhaust system for damage
Check and adjust ignition
Replace reed paddles or reed valve housing
Overhaul engine
REMEDY