Yamaha Motor YZ450F 2003 Manuel D'atelier Du Proprietaire page 260

EC466020
HANDLING NOTE
1
Do not loosen the screws {TPS (throttle
position sensor)} 1 except when changing
the TPS (throttle position sensor) due to
failure because it will cause a drop in
engine performance.
REMOVAL POINTS
Pilot screw
NOTE:
To optimize the fuel flow at a small throttle
opening, each machine's pilot screw has been
individually set at the factory. Before removing
the pilot screw, turn it in fully and count the
number of turns. Record this number as the
factory-set number of turns out.
INSPECTION
Carburetor
NOTE:
G
G
4 - 11
CARBURETOR
CAUTION:
1. Remove:
Pilot screw 1
G
1. Inspect:
Carburetor body
G
Contamination → Clean.
Use a petroleum based solvent for cleaning.
Blow out all passages and jets with com-
pressed air.
Never use a wire.
ENG