Yamaha 2001 YZ426F/LC Owner's Service Manual page 176

PILOT SCREW ADJUSTMENT
12. Check:
Checking steps:
Slightly loosen the oil gallery bolt 1.
Start the engine and keep it idling until oil
starts to seep from the oil gallery bolt. If no
oil comes out after one minute, turn the
engine off so it will not seize.
Check oil passages, oil filter and oil pump
for damage or leakage.
Start the engine after solving the prob-
lem(s) and recheck the oil pressure.
Tighten the oil gallery bolt to specification.
PILOT SCREW ADJUSTMENT
1. Adjust:
Adjusting steps:
NOTE:
To optimize the fuel flow at a smaller throttle
opening, each machine's pilot screw has
been individually set at the factory. Before
adjusting the pilot screw, turn it in fully and
count the number of turns. Record this num-
ber as the factory-set number of turns out.
Turn in the pilot screw until it is lightly
seated.
Turn out the pilot screw by the factory-set
number of turns.
3 - 17
Oil pressure
Oil gallery bolt:
18 Nm (1.8 m • kg, 13 ft • lb)
Pilot screw 1
Pilot screw:
1-1/4 turns out (example)
INSP
ADJ