KTM 640 LC4 Motorcycle User Manual


 
ENGLISH
42
TROUBLE
Engine fails to idle
Engine does not rev high
Engine will not reach full
power
Engine overheats
CAUSE
Glogged idling jet
Oncorrect adjustment of adjusting
screws on carburetor
Defective spark plug
Defective ignition system
Carburetor fuel level too high
because
Float needle is dirty or worn out
Float leaks
The cold starting system is perma-
nently activated due to a lack of
play in the choke cable.
Defective membrane of slide
Carburetor leaking
Loose carburettor jets
Electronic ignition timing faulty
Fuel supply partically interrupted or
carburetor dirty
Float leaks
Defective membrane of slide
Carburetor leaking
Air filter very dirty
Valve clearance to small
Loss of compression because hand
decompressor has no play
Electronic ignition timing faulty
Insufficient cooling liquid
Radiator fins are extremely dirty
Foam forms in cooling system
Bent radiator hose
Thermostat defective
Blown fan fuse
Defect thermoswitch
Fan defective
REMEDY
Disassemble carburetor and clean jets
Have carburetor adjusted
Replace spark plug
Have ignition system checked
Dismount carburetor and check if worn out
Replace float needle
Replace float
Adjust choke cable.
Replace membrane
Check vacuum hose and venting hose of carburetor for correct
position (no kinks)
Tighten jets
Have ignition system checked
Clean and check fuel system as well as carburetor
Replace the float
Replace membrane
Check vacuum hose and venting hose of carburetor for correct
position (no kinks)
Clean or replace air filter, contact a KTM dealer
Have valve clearance adjusted
Check setting of the hand decompression cable
Have ignition system checked
Refill cooling liquid (see maintenace work), check cooling
system for leaks
Clean radiator with water jet
Replace cooling liquid, use antifreezer with brand name
Shorten or replace cooling hose
Remove and check thermostat (opening temperature 70°C
(157°F) or replace it, contact a KTM dealer
Replace fuse and check if fan operates properly (see below)
Contact a KTM dealer
Check if fan operates properly. To do this, start the engine,
then bypass the connections to the thermoswitch (bottom
right radiator), contact a KTM dealer