Yamaha YZ250 2021 - Tuning

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TUNING
ENGINE.............................................................................................................8-1
CARBURETOR SETTING ..........................................................................8-1
ATMOSPHERIC CONDITIONS AND CARBURETOR SETTINGS ............8-1
TEST RUN..................................................................................................8-1
EFFECTS OF THE SETTING PARTS ON THE THROTTLE VALVE
OPENING ..................................................................................................8-2
MAIN JET ADJUSTMENT ..........................................................................8-2
ADJUSTING THE POWER JET .................................................................8-2
PILOT AIR SCREW ADJUSTMENT...........................................................8-2
PILOT JET ADJUSTMENT.........................................................................8-3
JET NEEDLE ADJUSTMENT.....................................................................8-3
JET NEEDLE GROOVE POSITION ADJUSTMENT..................................8-4
RELATIONSHIP WITH THROTTLE OPENING..........................................8-4
CARBURETOR SETTING PARTS .............................................................8-5
ROAD CONDITION AND EXAMPLES OF CARBURETOR SETTING.......8-6
EXAMPLES OF CARBURETOR SETTING DEPENDING ON
SYMPTOM.................................................................................................8-6
CHANGE OF THE HEAT RANGE OF SPARK PLUGS..............................8-8
CHASSIS ..........................................................................................................8-9
SELECTION OF THE SECONDARY REDUCTION RATIO
(SPROCKET).............................................................................................8-9
DRIVE AND REAR WHEEL SPROCKETS SETTING PARTS...................8-9
TIRE PRESSURE.......................................................................................8-9
FRONT FORK SETTING..........................................................................8-10
CHANGE IN AMOUNT AND CHARACTERISTICS OF FORK OIL..........8-10
SETTING OF SPRING AFTER REPLACEMENT.....................................8-10
FRONT FORK SETTING PARTS.............................................................8-11
REAR SUSPENSION SETTING...............................................................8-11
CHOOSING SET LENGTH.......................................................................8-11
SETTING OF SPRING AFTER REPLACEMENT.....................................8-12
REAR SHOCK ABSORBER SETTING PARTS .......................................8-12
SUSPENSION SETTING (FRONT FORK)...............................................8-14
SUSPENSION SETTING (REAR SHOCK ABSORBER)..........................8-15