2017 YAMAHA WR 250F engine

IMPORTANT INFORMATION
1-8
EAS2GBB022GASKETS, OIL SEALS AND O-RINGS
1. When overhauling the engine, replace all
gaskets and O-rings. All gasket surfaces, oil
seal lips, and O-rings must be cleaned so
that there may be no dust on them.
2. During assembly, always apply proper oil to
bearings and proper grease to oil seal lips
before installation.
EAS2GBB023LOCK WASHERS/PLATES AND COTTER
PINS
After removal, replace lock washers/plates “1”
and cotter pins with new ones. After the bolt or
nut has been tightened to specification, firmly
bend the lock tabs along a flat of the bolt or nut.
EAS2GBB024BEARINGS AND OIL SEALS
Install bearings “1” and oil seals “2” with their
manufacturer’s marks or size symbols facing
outward. During installation of an oil seal, make
sure that its main lip faces the oil chamber (the
target to be sealed). Before installation, always
apply a light coat of grease to the oil seal lip.
ECA
NOTICE
Do not spin the bearing with compressed air
because this will damage the bearing sur-
faces.
EAS2GBB025CIRCLIPS
When assembling parts, always use new cir-
clips. During installation of a circlip, make sure
that the edge “2” of the circlip “1” is positioned
opposite to the force “3” that the circlip re-
ceives. Install the circlip with its end aligned
with the center of the spline, without opening
the circlip more than necessary.
1. Oil
2. Lip
3. Spring
4. Grease

BASIC SERVICE INFORMATION
1-9
EAS2GBB026
BASIC SERVICE INFORMATION
EAS2GBB027ELECTRICAL SYSTEM
Electrical parts handling
ECA
NOTICE
Never disconnect a battery lead while the
engine is running; otherwise, the electrical
components could be damaged.
ECA
NOTICE
When disconnecting the battery leads from
the battery, be sure to disconnect the nega-
tive battery lead first, then the positive bat-
tery lead. If the positive battery lead is
disconnected first and a tool or similar item
contacts the vehicle, a spark could be gen-
erated, which is extremely dangerous.
TIP
If a battery lead is difficult to disconnect due to
rust on the battery terminal, remove the rust us-
ing hot water.
ECA
NOTICE
Be sure to connect the battery leads to the
correct battery terminals. Reversing the
battery lead connections could damage the
electrical components.
ECA
NOTICE
When connecting the battery leads to the
battery, be sure to connect the positive bat-
tery lead first, then the negative battery
lead. If the negative battery lead is connect-
ed first and a tool or similar item contacts
the vehicle while the positive battery lead is
being connected, a spark could be generat-
ed, which is extremely dangerous.
ECA
NOTICE
Make sure that the multi-function display
goes off after pushing and holding the en-
gine stop switch before disconnecting or
connecting any electrical components.

BASIC SERVICE INFORMATION
1-10
ECA
NOTICE
Handle electrical components with special
care, and do not subject them to strong
shocks.
ECA
NOTICE
Electrical components are very sensitive to
and can be damaged by static electricity.
Therefore, never touch the terminals and be
sure to keep the contacts clean.
TIP
Push and hold the engine stop switch to turn off
the multi-function display when resetting the
ECU (Electronic Control Unit). Disconnect the
starter motor lead of the starter relay, and then
push the starter switch. Be sure to wait for five
seconds or longer before pushing the start
switch after the multi-function display goes off.Checking the electrical system
TIP
Before checking the electrical system, make
sure that the battery voltage is at least 12 V.
ECA
NOTICE
Never insert the tester probes into the cou-
pler terminal slots. Always insert the probes
from the opposite end “a” of the coupler,
taking care not to loosen or damage the
leads.
ECA
NOTICE
For waterproof couplers, never insert the
tester probes directly into the coupler.
When performing any checks using a water-
proof coupler, use the specified test har-
ness or a suitable commercially available
test harness.
a

SPECIAL TOOLS
1-18
Digital tachometer
90890-06760
Digital tachometer
YU-39951-BThis tool is used to measure
the engine speed.
Yamaha bond No. 1215
90890-85505
(Three bond No.1215®)This sealant (Bond) is used
for crankcase mating sur-
face, etc. Tool name/Part number How to use Illustration

CONTROL FUNCTIONS
1-19
EAS2GBB029
CONTROL FUNCTIONS
EAS2GBB030INDICATOR LIGHTS AND WARNING
LIGHTS
Fuel level warning light “ ”
This warning light comes on when the fuel level
drops below approximately 2.1 L (0.55 US gal,
0.46 Imp.gal). When this occurs, refuel as soon
as possible.
The electrical circuit of the warning light can be
checked by pushing the start switch. The warn-
ing light should come on for a few seconds, and
then go off.
If the warning light does not come on initially
when the start switch is pushed, or if the warn-
ing light remains on, have a Yamaha dealer
check the electrical circuit.
Engine trouble warning light “ ”
This warning light comes on or flashes if a prob-
lem is detected in the electrical circuit monitor-
ing the engine. If this occurs, have a Yamaha
dealer check the vehicle.
The electrical circuit of the warning light can be
checked by pushing the start switch. The warn-
ing light should come on for a few seconds, and
then go off.
If the warning light does not come on initially
when the start switch is pushed, or if the warn-
ing light remains on, have a Yamaha dealer
check the electrical circuit.
EAS2GBB031ENGINE STOP SWITCH
The engine stop switch “1” is located on the left
handlebar. Continue pushing the engine stop
switch till the engine comes to a stop.
After the engine stops, the multi-function dis-
play will go off and the power supply to the ECU
(Electronic Control Unit) will be cut off if the en-
gine stop switch is pushed and held.
TIP
The multi-function display will go off after one
minute if the engine stop switch is not pushed.
EAS2GBB032START SWITCH
The start switch “1” is located on the right han-
dlebar. Push this switch to crank the engine
with the starter.
EAS2GBB033CLUTCH LEVER
The clutch lever “1” is located on the left han-
dlebar. The clutch lever disengages or engag-
es the clutch.
Pull the clutch lever toward the handlebar to
disengage the clutch, and release the lever to
engage the clutch.
EAS2GBB034
1. Engine trouble warning light “ ”
2. Fuel level warning light “ ”
12

CONTROL FUNCTIONS
1-20
SHIFT PEDAL
The shift pedal “1” has adopted a method of 1
down & 5 ups (press-down & kick-ups).
Press it down for N (neutral) to 1st, and kick it
up for 2nd to 6th.
Recommended shift points
The recommended shift points during accelera-
tion and deceleration are shown in the table be-
low.
EAS2GBB035KICKSTARTER LEVER
The kickstarter lever “1” is in the right of the
chassis.
To start the engine, pull out and push down the
kickstarter lever with your foot.
EAS2GBB036THROTTLE GRIP
The throttle grip “1” is located on the right han-
dlebar. The throttle grip accelerates or deceler-
ates the engine. For acceleration, turn the grip
toward you; for deceleration, turn it away from
you.
EAS2GBB037FRONT BRAKE LEVER
The front brake lever “1” is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
EAS2GBB038REAR 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.
EAS2GBB039
Shift up points
1st  2nd: 20 km/h (12 mi/h)
2nd  3rd: 30 km/h (19 mi/h)
3rd  4th: 40 km/h (25 mi/h)
4th  5th: 50 km/h (31 mi/h)
5th  6th: 60 km/h (37 mi/h)
Shift down points
6th  5th: 45 km/h (28 mi/h)
5th  4th: 35 km/h (22 mi/h)
4th  3rd: 25 km/h (16 mi/h)
3rd  2nd: 25 km/h (16 mi/h)
2nd  1st: 25 km/h (16 mi/h)
1
1
1

CONTROL FUNCTIONS
1-21
SIDESTAND
This sidestand “1” is used to support only the
machine when standing or transporting it.
EWA
WARNING
• Never apply additional force to the sides-
tand.
• Hold up the sidestand before starting out.
EAS2GBB040STARTER KNOB/IDLE 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.
EAS2GBB041FUEL 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

STARTING AND BREAK-IN
1-30
EAS2GBB048
STARTING AND BREAK-IN
EAS2GBB049FUEL
Always use the recommended fuel as stated
below. Also, be sure to use new gasoline the
day of a race.
ECA
NOTICE
Use only unleaded gasoline. The use of
leaded gasoline will cause severe damage
to the engine internal parts such as valves,
piston rings, and exhaust system, etc.
TIP
Your Yamaha engine has been designed to use
premium unleaded gasoline with a pump oc-
tane number [(R+M)/2] of 91 or higher, or a re-
search octane number of 95 or higher. If
knocking (or pinging) occurs, use a gasoline of
a different brand.
EWA
WARNING
• For refueling, be sure to stop the engine
and use enough care not to spill any fuel.
Also be sure to avoid refueling close to a
fire.
• Refuel after the engine, exhaust pipe, etc.
have cooled off.
Gasohol (For USA and Canada)
There are two types of gasohol: gasohol con-
taining ethanol and that containing methanol.
Gasohol containing ethanol can be used if the
ethanol content does not exceed 10%. Gasohol
containing methanol is not recommended by
Yamaha because it can cause damage to the
fuel system or vehicle performance problems.
EAS2GBB050HANDLING NOTEEWA
WARNING
Never start or run the engine in a closed ar-
ea. The exhaust fumes are poisonous; they
can cause loss of consciousness and death
in a very short time. Always operate the ma-
chine in a well-ventilated area.
ECA
NOTICE
• Unlike a two-stroke engine, this engine
cannot be kick started when the throttle is
open because the kickstarter may kick
back. Also, if the throttle is open the air/
fuel mixture may be too lean for the engine
to start.
• Before starting the machine, perform the
checks in the pre-operation check list.
EAS2GBB051AIR FILTER MAINTENANCE
According to “CLEANING THE AIR FILTER
ELEMENT” section in the CHAPTER 3, apply
the Yamaha foam air filter oil or other quality
foam air filter oil to the element. (Excess oil in
the element may adversely affect engine start-
ing.)
EAS2GBB052STARTING A COLD ENGINEECA
NOTICE
For maximum engine life, never accelerate
hard when the engine is cold!
In order for the ignition circuit cut-off system to
enable starting, one of the following conditions
must be met:
• The transmission is in the neutral position.
• The transmission is in gear with the clutch le-
ver pulled.
1. Pull the starter knob/idle screw “1” to its full
length.
TIP
When the ambient temperature is 15°C (59°F)
or below, use the starter knob/idle screw.
2. Completely close the throttle. Recommended fuel
Premium unleaded gasoline
only
Fuel tank capacity
7.5 L (2.0 US gal, 1.7 lmp.gal)
Fuel reserve amount
2.1 L (0.55 US gal, 0.46 lmp.gal)
1