Pilot System; Main Jet Adjustment; Effects Of Changing The Main Jet (Reference) - Yamaha YZ426F(P) Owner's Service Manual

SETTING

Pilot system

The FLATCR carburetor is manufactured with
a pilot screw. The pilot screw adjustment
ranges from fully closed throttle to 1/4 open
throttle.

Main jet adjustment

The richness of the air-fuel mixture at full throt-
tle can be set by changing the main jet 1.
Standard main jet
If the air-fuel mixture is too rich or too lean, the
engine power will drop, resulting in poor accel-
eration.

Effects of changing the main jet (reference)

Å
1/4
Å Idle ı Fully open
7 - 4
T U N
#162
ı
1/2 3/4
#172
#152
+10%
#162
–10%