Carburetor; Choke; Carburetor - Adjusting The Idle Speed - KTM 250 EXC EU Repair Manual

19

CARBURETOR

19.1

Choke

19.2

Carburetor - adjusting the idle speed

The choke lever
Activating the choke function frees an opening in the carburetor through which the
engine can draw extra fuel. This creates a richer fuel-air mixture, as is required for a
cold start.
Info
If the engine is warm, the choke function must be deactivated.
Possible states
Choke function activated – The choke lever is pulled out all the way.
•
B00004-10
Choke function deactivated – The choke lever is pushed in all the way.
•
–
Screw in idle air adjusting screw
position.
Guideline
Idle air adjusting screw (all 250/300 XC‑W)
Open
Idle air adjusting screw (250/300 EXC AUS)
Open
Idle air adjusting screw (250 EXC EU, 250 EXC SIX DAYS EU)
B00048-11
Open
Idle air adjusting screw (300 EXC EU, 300 EXC SIX DAYS EU)
Open
–
Run the engine until warm.
Guideline
Warm-up time
Danger
Danger of poisoning Exhaust gases are toxic and inhaling them may result
in unconsciousness and/or death.
–
–
Adjust the idle speed with adjusting screw
Guideline
Choke function deactivated – The choke lever is pushed in all the way.
( p. 186)
Idle speed
–
Turn idle air adjusting screw
begins to fall.
–
Note the position and turn the idle air adjusting screw slowly counterclockwise until
the idle speed falls again.
–
Adjust to the point between these two positions with the highest idle speed.
Info
If there is a large engine speed rise, reduce the idle speed to a normal level
and repeat the above steps.
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 air adjusting screw to the end without any change of
engine speed, you need to install a smaller idling jet.
After changing the idling jet, repeat the adjusting steps from the beginning.
Following extreme air temperature or altitude changes, adjust the idle speed
again.
is fitted on the left side of the carburetor.
1
all the way and turn it to the specified basic
2
When running the engine, always make sure there is sufficient ventila-
tion, and do not start or run the engine in an enclosed space without an
effective exhaust extraction system.
slowly in a clockwise direction until the idle speed
2
2.0 turns
3.5 turns
1.5 turns
1.75 turns
≥ 5 min
.
1
1,400... 1,500 rpm
186