Yamaha WR426F(P), 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
4/4
3/4
1/2
1/4
1/8
0
ı
Å
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. The main air jet has
almost no effect on the air-fuel mixture. Use
the main jet and the jet needle to set the car-
buretor.
1 Jet needle
2 Main air jet
3 Pilot air jet
4 Needle jet
5 Main jet
6 Pilot jet
7 Pilot screw