Yamaha YZ450F(S), Owner'S Service Manual

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7 - 3
T U N
SETTING
Effects of the setting parts on the throttle
valve opening
1 Pilot screw/pilot jet
2
Throttle valve cutaway
3 Jet needle
4 Main jet
Å
Closed
ı
Fully open
1/2 3/4
1/4 1/8
1
2
3
4
Å ı
Main system
The FLATCR carburetor has a primary main
jet. This type of main jet is perfect for racing
motorcycles since it supplies an even flow of
fuel, even at full load. Use the main jet and the
jet needle to set the carburetor.
1 Jet needle
2 Pilot air jet
3 Needle jet
4 Main jet
5 Pilot jet
6 Pilot screw