Carburetor - Adjusting Idle - KTM 450 SX-F Owner's Manual

MAINTENANCE WORK ON CHASSIS AND ENGINE

Carburetor - adjusting idle

8.111
x
–
Screw in the idle adjusting screw
setting.
Rules
Idle mixture adjusting screw
Open
Adjustment tool for mixture control screw (77329034000)
–
Run the engine until warm.
Rules
400266-10
Warm-up time:
–
Adjust the idle speed with the adjusting screw
Rules
Choke function deactivated (
Idle speed
–
Turn the idle adjusting screw
–
Note the position and turn the idle adjusting screw slowly counterclockwise until the
idle speed falls.
–
Adjust to the point between these two positions with the highest idle speed.
Info
If there is a big engine speed rise, reduce the idle speed to a normal level
and repeat the above steps.
The extreme sport motocyclist will set the mixture about 1/4 of a turn back
from this ideal value (leaner, in a clockwise direction) since the engine
becomes hotter in sporting use.
If the procedure described here does not lead to satisfactory results, the
cause may be a wrongly dimensioned idling jet.
If you can turn the idle adjusting screw to the end without any change of
engine speed, you have to fit a smaller idling jet.
The idle adjusting screw must not be opened more than two turns. If more
than two turns are necessary (rich mixture), use a larger idling jet.
After changing the idling jet, start from the beginning with the adjusting
steps.
–
Adjust the idle speed with the adjusting screw
Rules
Choke function deactivated (
Idle speed
Info
Following extreme air temperature or altitude changes, adjust the idle speed
again.
until it stops and then to the prescribed basic
2
1.5 turns
≥ 5 min
.
1
10)
1600...1650 rpm
slowly until the idle speed begins to fall.
2
.
1
10)
1600...1650 rpm
62