Yamaha WR400F 1999 Manual De Servicio página 618

Å Lean (larger diameter)
ı Rich (smaller diameter)
1 1/8 throttle
2 1/4 throttle
3 1/2 throttle
4 1/1 throttle
a Main nozzle
SETTING
Relationship with throttle opening
The flow of the fuel through the carburetor
main system is controlled by the main jet and
then, it is further regulated by the area
between the main nozzle and the jet needle.
The fuel flow relates to the diameter of the
straight portion of the jet needle with the throt-
tle 1/8 to 1/4 open and relates to the taper
starting position and the clip position with the
throttle 1/4 to fully open.
Therefore, the fuel flow is balanced at each
stage of throttle opening by the combination of
the jet needle straight portion diameter, taper
starting position and clip position.
7 - 7
T U N