KTM 450 XC Owner's Manual page 162

MAINTENANCE ON CHASSIS AND ENGINE
–
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 extremely sporty rider 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
Guideline
Choke function deactivated – The choke lever is pushed in to the stop. (
Idle speed
Info
Following extreme air temperature or altitude changes, adjust the idle speed
again.
.

1,500... 1,600 rpm
160
p. 38)