KTM 250 XC-W 2018 Owner's Manual page 157

Carburetor identification number
Needle position
Jet needle
Main jet
Idling jet
Starting jet
Needle jet
Idle air adjusting screw
Open
Throttle slide
22.3.4 Carburetor tuning (All XC‑W models)
M/FT ASL
TEMP
ASO
TMX 38 80
2nd position from top
6BFY43‑75 (6BFY42-75)
450 (430, 440, 460)
25 (22.5/27.5)
80
S-4
1.5 turns
4
Sea level
Temperature
Idle air adjusting screw open
22 TECHNICAL DATA
402896-01
155