19 Troubleshooting - KTM 85 SX 2021 Owner's Manual

19 TROUBLESHOOTING

Faults
Engine turns but does not start
Engine has no idle
Engine does not speed up
Engine has too little power
112
Possible cause
Operating error
Motorcycle was out of use for a
long time and there is old fuel
in the float chamber
Fuel feed interrupted
Spark plug oily or wet
Plug gap of spark plug too wide
Fault in ignition system
Short-circuit cable in wiring
harness frayed, switch-off but-
ton faulty
Water in carburetor or jets
blocked
Idling jet blocked
Adjusting screws on carburetor
distorted
Spark plug defective
Ignition system defective
Carburetor running over
because float needle dirty or
worn
Loose carburetor jets
Fault in ignition system
Fuel feed interrupted
Air filter is very dirty
Exhaust system leaks,
deformed or too little glass
fiber yarn filling in main
silencer
Fault in ignition system
Membrane or reed valve hous-
ing is damaged
Action
–
Carry out the start procedure.
( p. 26)
–
Empty the carburetor float chamber.
( p. 102)
–
Check the fuel tank breather.
–
Clean the fuel tap.
–
Check/set the carburetor components.
–
Clean and dry the spark plug, or
change it if necessary.
–
Adjust plug gap.
Guideline
Spark plug electrode gap
0.60 mm (0.0236 in)
–
Check the ignition system.
–
Adjust the ignition.
–
Check the switch-off button.
–
Check/set the carburetor components.
–
Check/set the carburetor components.
– Carburetor – adjust the idle speed.
( p. 101)
–
Change the spark plug.
–
Check the ignition coil.
–
Check the spark plug connector.
–
Check/set the carburetor components.
–
Check/set the carburetor components.
–
Check the ignition system.
–
Adjust the ignition.
–
Check the fuel tank breather.
–
Clean the fuel tap.
–
Check/set the carburetor components.
–
Clean the air filter and air filter box.
( p. 57)
–
Check exhaust system for damage.
–
Change the glass fiber yarn filling of
the main silencer. (
–
Check the ignition system.
–
Adjust the ignition.
–
Check the membrane and reed valve
housing.
p. 58)