Yamaha TT600R Service Manual page 288

SECTION VIEW
(1) Needle jet (primary)
(2) Valve seat
(3) Needle valve
(4) Main nozzle (primary)
(5) Main jet (primary)
(6) Pilot air screw
(7) Needle jet (secondary)
A
CARBURETOR
(8) Main nozzle (secondary)
(9) Main jet (secondary)
[A] Primary carburetor
[B] Secondary carburetor
Air
Fuel
Mixture
6-5
CARB
B