KTM 400-660 LC4 1998-2005 Repair Manual page 218

9-3E
TROUBLE
Engine will not reach full
power
Engine stops or splutters
in carburettor
Engine gets to hot,
High oil consumption
All switched on lamps
blown out
CAUSE
Fuel supply partically interrupted or
carburettor dirty
Float is not tight, or no axial play
Air filter very dirty
Exhaust leaking or blocked
Valve gap to small
Loss of compression because hand
decompressor has no play
Electronical ignition timing faulty
Insuffient fuel
Engine takes air out of control
Insufficient cooling liquid
Not enough air stream
Radiators very dirty
Foam formation in cooling system
Bent cooling hose
Thermostat defective
Buckling gearing ventilation hose
Engine oil level too high
Motor oil too thin (viscosity)
Capacitor or voltage regulator
faulty
REMEDY
Clean and check fuel system as well as carburettor
Replace or abrade the float
Clean or replace air filter
Check if exhaust is damaged, replace glas fibre yarn in
exhaust silencer
Adjust valve gap
Check setting of the hand decompression cable
Check ignition system
Clean and check fuel system and carburettor
Check intake flange and carburettor if firmly setted
Refill cooling liquid (see maintenace work), check cooling
system for leaks
Drive on briskly
Clean radiators with water jet
Replace cooling liquid, use anti freeze liquid with brand
name
Shorten or replace cooling hose
Dismount and check thermostat (opening temperature 70°
C, 158° F) or replace it
Dislocate i.e. replace non-buckling vetilation hose
Check engine oil level when the engine is warm; correct if necessary
Use thicker engine oil; see chapter „Engine oil"
Remove right side cover and control connections. Check
capacitor and voltage regulator