Main Jet Adjustment; Effects Of Changing The Main Jet (Reference); Pilot Jet Adjustment; Effects Of Adjusting The Pilot Jet (Reference) - Yamaha WR450F(V) Owner's Service Manual

SETTING

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)

È
1/4
È Idle
É Fully open

Pilot jet adjustment

The richness of the air-fuel mixture with the
throttle open 1/4 or less can be set by adjust-
ing the pilot jet 1.
Standard pilot jet

Effects of adjusting the pilot jet (reference)

È
1/4
#48
#42
È Idle
É Fully open
7 - 4
T U N
#165
É
1/2 3/4
#175
#155
#45
1/2 3/4
+10%
#165
–10%
É
+5%
#45
–5%