Yamaha YZ85(V), Owner'S Service Manual

Page: 468 / 508

7 - 3
T U N
SETTING
Effects of the setting parts on the throttle
valve opening
1
Throttle valve opening
2
Full-open
3
Full-closed
Setting part
Throttle valve opening
Full-closed1/4 1/2 3/4 Full-open
Pilot jet
Pilot air screw
Jet nee
dle
Diameter of
straight por-
tion
Clip position
Main jet
5PA70040
Main jet adjustment
The richness of air-fuel mixture with 3/4 ~ 4/4
throttle can be set by changing the main jet
1
.
1. Spark plug is too hot.
Select a main jet having higher calibrating
No. than standard. (To be enriched)
2. Spark plug is wet.
Select a main jet having lower calibrating
No. than standard. (To be leaned out)
Standard main jet #138
5PA70050
Pilot air screw adjustment
The richness of the air-fuel mixture with the
throttle fully closed to 1/4 open can be set by
turning the pilot air screw
1
.
Turning in the pilot air screw will make the mix-
ture enrich at low speeds, and turning it out will
lean it.
Standard pilot air
screw position
2 turns out
(example)
5PA70060