Carburetor Tuning - KTM 85 SX 2022 Owner's Manual

15.3

Carburetor tuning

Effects of carburetor tuning
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.
–
Turn barrel adjuster
cable at the throttle grip.
Guideline
Play in throttle cable
–
3
Tighten nut
–
Slide on sleeve
400192-11
Finishing work
–
Install the fuel tank.
–
Mount the seat. (
–
Check the play in the throttle cable. (
TUNING THE ENGINE 15
2
so that there is play
2 ... 3 mm (0.08 ...
0.12 in)
.
1
.
( p. 62)
p. 56)
p. 98)
A
in the throttle
H01400-01
99