KTM 50 SX JUNIOR - Manual (Page 33)

TROUBLE SHOOTING
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ENGLISH
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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 CAUSE REMEDY
Engine fails to start Operating error
The motorcycle was not driven for a longer
period of time, leaving old fuel in the float
chamber
Fuel supply interrupted
Electrode distance too large
Plug fouled by oil, wet or bridged
Ignition wire or spark plug connector
damaged
Kill button wire or short-circuit switch
faulty
Loose ignition cable connectors
Spark too weak
Water in the carburetor and jets blocked
Open fuel tap, replenish fuel, do not use choke
The highly inflammable components in modern fuels volatilize
if left standing for longer periods of time. If the motorcycle
has not been used for over 1 week, the fuel should be drained
from the float chamber. The engine will start up immediately
if the float chamber is filled with fresh, ignitable fuel
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
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 igni-
tion cable, hold about 5 mm from ground and actuate kick-
starter
– 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 carbureto
Engine without idle running Idle adjusting screw out of adjustment
Ignition system damaged
Wear
Readjust idle running or replace idle adjusting screw
Examine ignition system
Overhaul engine
Less power of engine 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 damaged, sur-
face of reed valve housing damaged
Wear
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