KTM 85 SX 17/14 2021, Owner'S Manual

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15 TUNING THE ENGINE
98
400192-11
–
Turn barrel adjuster
2
so that there is play
A
in the throttle
cable at the throttle grip.
Guideline
Throttle cable play 2 … 3 mm (0.08 …
0.12 in)
–
Tighten nut
3
.
–
Slide on sleeve 1 .
Finishing work
–
Install the fuel tank. ( p. 61)
–
Mount the seat. ( p. 55)
–
Check the throttle cable play. ( p. 97)
15.3 Carburetor tuning
Effects of carburetor tuning
H01400-01
The different carburetor components must be tuned both to one another and for the use intended.
Main jet MJ
The main jet MJ has the greatest influence with the throttle slide open (full throttle).
If the insulator of a new spark plug is very light or white after a brief ride at full throttle, or if the engine knocks, a
larger main jet needs to be used. If the insulator is dark brown or sooty, a smaller main jet needs to be used.
Needle position POS
The needle position has the greatest influence in the mid throttle slide range.
If the engine stutters when accelerating with a partially open throttle slide, the jet needle must be lowered. If the
engine knocks when accelerating at the full power rpm range, the jet needle must be raised.
Cylindrical part of the needle CYL
The cylindrical part of the needle has the greatest influence when the throttle slide is almost closed.