2016 YAMAHA YZ250F fuel

EAS1SM9005
SAFETY INFORMATION
THIS MACHINE IS DESIGNED STRICTLY FOR COMPETITION USE, ONLY ON A CLOSED
COURSE. It is illegal for this machine to be operated on any public street, road, or highway. Off-road
use on public lands may also be illegal. Please check local regulations before riding.
• THIS MACHINE IS TO BE OPERATED BY AN EXPERIENCED RIDER ONLY.
Do not attempt to operate this machine at maximum power until you are totally familiar with its char-
acteristics.
• THIS MACHINE IS DESIGNED TO BE RIDDEN BY THE OPERATOR ONLY.
Do not carry passengers on this machine.
• ALWAYS WEAR PROTECTIVE APPAREL.
When operating this machine, always wear an approved helmet with goggles or a face shield. Also
wear heavy boots, gloves, and protective clothing. Always wear proper fitting clothing that will not
be caught in any of the moving parts or controls of the machine.
• ALWAYS MAINTAIN YOUR MACHINE IN PROPER WORKING ORDER.
For safety and reliability, the machine must be properly maintained. Always perform the pre-oper-
ation checks indicated in this manual.
Correcting a mechanical problem before you ride may prevent an accident.
• GASOLINE IS HIGHLY FLAMMABLE.
Always turn off the engine while refueling. Take care to not spill any gasoline on the engine or ex-
haust system. Never refuel in the vicinity of an open flame, or while smoking.
• GASOLINE CAN CAUSE INJURY.
If you should swallow some gasoline, inhale excess gasoline vapors, or allow any gasoline to get
into your eyes, contact a doctor immediately. If any gasoline spills onto your skin or clothing, imme-
diately wash skin areas with soap and water, and change your clothes.
• ONLY OPERATE THE MACHINE IN AN AREA WITH ADEQUATE VENTILATION.
Never start the engine or let it run for any length of time in an enclosed area. Exhaust fumes are
poisonous. These fumes contain carbon monoxide, which by itself is odorless and colorless. Car-
bon monoxide is a dangerous gas which can cause unconsciousness or can be lethal.
• PARK THE MACHINE CAREFULLY; TURN OFF THE ENGINE.
Always turn off the engine if you are going to leave the machine. Do not park the machine on a slope
or soft ground as it may fall over.
• THE ENGINE, EXHAUST PIPE AND MUFFLER WILL BE VERY HOT AFTER THE ENGINE HAS
BEEN RUN.
Be careful not to touch them or to allow any clothing item to contact them during inspection or repair.
• PROPERLY SECURE THE MACHINE BEFORE TRANSPORTING IT.
For safety, drain the gasoline from the fuel tank before transporting the vehicle.

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10 TABLE OF CONTENTS
GENERAL INFORMATION
SPECIFICATIONS
PERIODIC CHECKS AND
ADJUSTMENTS
CHASSIS
ENGINE
COOLING SYSTEM
FUEL SYSTEM
ELECTRICAL SYSTEM
TROUBLESHOOTING
TUNING

1
GENERAL INFORMATION
LOCATION OF IMPORTANT LABELS............................................................ 1-1
DESCRIPTION.................................................................................................. 1-4
IDENTIFICATION............................................................................................. 1-5
VEHICLE IDENTIFICATION NUMBER ...................................................... 1-5
ENGINE SERIAL NUMBER ....................................................................... 1-5
INCLUDED PARTS.......................................................................................... 1-6
SIDESTAND ............................................................................................... 1-6
SPARK PLUG WRENCH ........................................................................... 1-6
NIPPLE WRENCH...................................................................................... 1-6
HANDLEBAR PROTECTOR ...................................................................... 1-6
FUEL HOSE JOINT COVER ...................................................................... 1-6
COUPLER FOR CONNECTING OPTIONAL PART................................... 1-6
IMPORTANT INFORMATION.......................................................................... 1-8
PREPARATION FOR REMOVAL AND DISASSEMBLY............................ 1-8
REPLACEMENT PARTS............................................................................ 1-8
GASKETS, OIL SEALS AND O-RINGS ..................................................... 1-9
LOCK WASHERS/PLATES AND COTTER PINS ...................................... 1-9
BEARINGS AND OIL SEALS ..................................................................... 1-9
CIRCLIPS ................................................................................................... 1-9
BASIC SERVICE INFORMATION.................................................................. 1-10
ELECTRICAL SYSTEM............................................................................ 1-10
SPECIAL TOOLS........................................................................................... 1-13
CONTROL FUNCTIONS................................................................................ 1-18
ENGINE STOP SWITCH .......................................................................... 1-18
CLUTCH LEVER...................................................................................... 1-18
SHIFT PEDAL .......................................................................................... 1-18
KICKSTARTER LEVER............................................................................ 1-18
THROTTLE GRIP ..................................................................................... 1-18
FRONT BRAKE LEVER ........................................................................... 1-18
REAR BRAKE PEDAL.............................................................................. 1-19
STARTER KNOB/IDLE ADJUSTING SCREW ......................................... 1-19
FUEL TANK CAP ..................................................................................... 1-19

STARTING AND BREAK-IN.......................................................................... 1-20
FUEL ........................................................................................................ 1-20
STARTING A COLD ENGINE .................................................................. 1-20
STARTING A WARM ENGINE ................................................................. 1-21
BREAK-IN PROCEDURES ...................................................................... 1-21
MAINTENANCE AFTER BREAK-IN.............................................................. 1-22
MAJOR MAINTENANCE .......................................................................... 1-22
TORQUE-CHECK POINTS............................................................................ 1-23
CLEANING AND STORAGE.......................................................................... 1-25
CLEANING ............................................................................................... 1-25
STORAGE ................................................................................................ 1-25

DESCRIPTION
1-4
EAS1SM9009
DESCRIPTION
TIP
Designs and specifications of the vehicle are subject to change without notice. Therefore, please
note that the descriptions in this manual may be different from those for the vehicle you have pur-
chased.1. Clutch lever 10. Coolant drain bolt
2. Front brake lever 11. Rear brake pedal
3. Throttle grip 12. Air filter
4. Radiator cap 13. Drive chain
5. Fuel tank cap 14. Shift pedal
6. Engine stop switch 15. Oil level check window
7. Fuel tank 16. Starter knob/idle screw
8. Kickstarter lever 17. Front fork
9. Radiator
2 1
6
78 954 3
11 10 17 16 15 14 1312

INCLUDED PARTS
1-6
EAS1SM9013
INCLUDED PARTS
EAS1SM9014SIDESTAND
The sidestand “1” is used to support only the
machine when standing or transporting it.
EWA@
WARNING
• Never apply additional force to the sides-
tand.
• Remove this sidestand before starting out.
EAS1SM9015SPARK PLUG WRENCH
The spark plug wrench “1” is used to remove or
install the spark plug.
EAS1SM9016NIPPLE WRENCH
The nipple wrench “1” is used to tighten the
spoke.
EAS1SM9017HANDLEBAR PROTECTOR
Install the handlebar protector “1” with the mark
“a” facing forward.
EAS1SM9018FUEL HOSE JOINT COVER
The fuel hose joint covers “1” are used to pre-
vent mud, dust, and other foreign materials
from entering the inside when the fuel hose is
disconnected.
EAS1SM9019COUPLER FOR CONNECTING OPTIONAL
PART
The coupler “1” is used for connecting the op-
tional Power Tuner and so on.
ECA
NOTICE
When no optional parts, etc. are connected,
connect the connection terminal to the orig-
inal coupler.
Before disconnecting the coupler, thor-
oughly wipe off any mud or water stuck to it.
1
1
a
1A
A
1
1

SPECIAL TOOLS
1-15
Pocket tester
90890-03112
Analog pocket tester
YU-03112-CThis tool is used to measure
the voltage, current, and re-
sistance of electrical compo-
nents.
Timing light
90890-03141
YU-03141This tool is used to measure
the ignition timing.
Pressure gauge
90890-03153
YU-03153This tool is used to measure
the fuel pressure.
Fuel pressure adapter
90890-03186
YM-03186This tool is used to mount the
pressure gauge.
Test harness S-pressure
sensor (3P)
90890-03207
YU-03207This tool is used to check the
throttle position sensor input
voltage.
FI diagnostic tool sub-lead
90890-03212
YU-03212This tool is used to connect
the Yamaha diagnostic tool
to a battery.
Yamaha diagnostic tool
90890-03231
Yamaha diagnostic tool (US)
90890-03234This tool is used to check er-
ror codes or carry out self-di-
agnosis.
Valve spring compressor
90890-04019
YM-04019This tool is used to discon-
nect or connect the valve and
the valve spring. Tool name/Part number How to use Illustration
YM-04019

CONTROL FUNCTIONS
1-19
EAS1SM9036REAR BRAKE PEDAL
The rear brake pedal “1” is in the right of the
chassis. Press down on the brake pedal to ac-
tivate the rear brake.
EAS1SM9037STARTER KNOB/IDLE ADJUSTING SCREW
Starting a cold engine requires a larger amount
of intake air, which is supplied by the starter
knob/idle screw “1”.
Pulling the knob toward “a” turns ON the start-
er, resulting in a larger amount of intake air.
Pushing the knob toward “b” turns OFF the
starter.
EWA
WARNING
While handling the starter knob/idle screw,
take care not to burn yourself on exhaust
pipes.
EAS1SM9038FUEL TANK CAP
Fuel tank cap “1” is located under the fuel tank
cap cover “2”.
Remove the fuel tank cap cover to open the fuel
tank cap.
TIP
• To remove the fuel tank cap cover, insert fin-
gers under part “a”, and then use both hands
to lift it up towards the rear of the vehicle.
• Install the fuel tank cap cover after placing the
bands “3” all the way in under the seat.
1
ab1
1
23
a
2