2016 YAMAHA YZ250F engine

ENGINE
3-19
c. Check the number on the originally installed
adjusting pad.
TIP
• The adjusting pad number “a” is indicated on
the top of the adjusting pad.
• For the number on the originally installed ad-
justing pad, convert the last digit of adjusting
pad number as per the below table.
d. Select an adjusting pad with a proper valve
clearance from the adjusting pad selection
table.
TIP
• There are 25 types of adjusting pads, ranging
from 1.20 mm (0.0472 in) to 2.40 mm (0.0945
in), in increments of 0.05 mm (0.0020 in).
• The field where the number on the originally
installed adjusting pad and the measured
valve clearance intersect shows the adjusting
pad number to replace.
Example:
Pad number = 148
Rounded value = 150
e. Install the new adjusting pads “4” and the
valve lifters “5”.
ECA@
NOTICE
Do not twist adjusting pads and valve lifters
forcibly during installation.
TIP
• Apply the engine oil on the valve lifters.
• Apply molybdenum disulfide oil to the valve
stem ends.
• Check that the valve lifters turn smoothly
when rotated with your finger.
• Make sure that valve lifters and adjusting
pads are installed in place.
• Make sure that adjusting pads are installed
with their numbers facing upward.
f. Install the camshafts (exhaust and intake).
Refer to “CAMSHAFT” on page 5-11.
g. Measure the valve clearance again.
h. If the valve clearance is out of specification,
repeat adjusting the valve clearance until it
is within specification.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
Last digit of pad
numberRounded valve
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10
4 5

ENGINE
3-20
INTAKE
Example:
Valve clearance (cold) 0.12–0.19 mm
(0.0047–0.0075 in)
Installed is 175
Measured clearance 0.27 mm (0.0106 in)
Replace 175 pad with 185 pad
Pad No.175 = 1.75 mm (0.0689 in)
Pad No.185 = 1.85 mm (0.0728 in)
0.12 0.19
0.250.29 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.30
0.34 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.35
0.39 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.40
0.44 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.45
0.49 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.50
0.54 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.55
0.59 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.60
0.64 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.65
0.69 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.70
0.74 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.75
0.79 180 185 190 195 200 205 210 215 220 225 230 235 240
0.80
0.84 185 190 195 200 205 210 215 220 225 230 235 240
0.85
0.89 190 195 200 205 210 215 220 225 230 235 240
0.90
0.94 195 200 205 210 215 220 225 230 235 240
0.95
0.99 200 205 210 215 220 225 230 235 240
1.00
1.04 205 210 215 220 225 230 235 240
1.05
1.09 210 215 220 225 230 235 240
1.10
1.14 215 220 225 230 235 240
1.15
1.19 220 225 230 235 240
1.20
1.24 225 230 235 240
1.25
1.29 230 235 240
1.30
1.34 235 240
1.35
1.39 240
120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.02 0.06
120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 0.00
0.01120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.07 0.11 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235
0.20 0.24 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
A. Measured clearance
B. Installed pad number
C. Standard clearance

ENGINE
3-21
EXHAUST
Example:
Valve clearance (cold) 0.17–0.24 mm
(0.0067–0.0094 in)
Installed is 175
Measured clearance 0.32 mm (0.0126 in)
Replace 175 pad with 185 pad
Pad No.175 = 1.75 mm (0.0689 in)
Pad No.185 = 1.85 mm (0.0728 in)
0.17 0.24
0.25
0.29 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.30
0.34 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.35
0.39 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.40
0.44 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.45
0.49 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.50
0.54 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.55
0.59 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.60
0.64 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.65
0.69 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.70
0.74 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.75
0.79 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.80
0.84 180 185 190 195 200 205 210 215 220 225 230 235 240
0.85
0.89 185 190 195 200 205 210 215 220 225 230 235 240
0.90
0.94 190 195 200 205 210 215 220 225 230 235 240
0.95
0.99 195 200 205 210 215 220 225 230 235 240
1.00
1.04 200 205 210 215 220 225 230 235 240
1.05
1.09 205 210 215 220 225 230 235 240
1.10
1.14 210 215 220 225 230 235 240
1.15
1.19 215 220 225 230 235 240
1.20
1.24 220 225 230 235 240
1.25
1.29 225 230 235 240
1.30
1.34 230 235240
1.35
1.39 235 240
1.40
1.44 240 0.00
0.01 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220
0.02
0.06 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.07
0.11 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.12
0.16 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235
120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
A. Measured clearance
B. Installed pad number
C. Standard clearance

CHASSIS
3-28
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor
lock.
ECA
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
EAS1SM9096ADJUSTING THE DRIVE CHAIN SLACKECA13550
NOTICE
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci-
fied limits.
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Shift the transmission into the neutral posi-
tion.
3. Pull the drive chain up above the drive chain
guide installation bolt with a force of about
50 N (5.0 kgf, 36 lbf).
4. Check:
• Drive chain slack “a”
Out of specification  Regulate.
TIP
Measure drive chain slack between the drive
chain guide and the bottom of the chain as
shown.5. Adjust:
• Drive chain slack
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Loosen the wheel axle nut “1”.
b. Loosen both locknuts “2”.
c. Turn the adjusting bolt “3” in direction “a” or
“b” until the specified drive chain slack is ob-
tained.
TIP
• To maintain the proper wheel alignment, ad-
just both sides evenly.
• Push the rear wheel forward to make sure that
there is no clearance between the swingarm
end plates and the ends of the swingarm.
d. Tighten the locknut.
e. Tighten the wheel axle nut.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
Drive chain slack
50–60 mm (1.97–2.36 in)
Direction “a”
The drive chain slack decreases.
Direction “b”
The drive chain slack increases.
Locknut
21 Nm (2.1 m·kgf, 15 ft·lbf)
Wheel axle nut
135 Nm (13.5 m·kgf, 98 ft·lbf)
a
1
32
a
b
T R..
T R..

ELECTRICAL SYSTEM
3-37
2. Attach:
• Timing light “1”
• Digital tachometer “2”
To the high tension code “3”.
3. Adjust:
• Engine idling speed
Refer to “ADJUSTING THE ENGINE
IDLING SPEED” on page 3-16.
4. Check:
• Ignition timing
Check whether the alignment mark “a” on
the left crankcase cover is within the firing
range “b” on the rotor.
Incorrect firing range  Check rotor and
Crankshaft position sensor.
5. Install:
• Timing mark accessing screwTiming light
90890-03141
YU-03141
Digital tachometer
90890-06760
YU-39951-B
Timing mark accessing screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
2
1
3
a
b
T R..

GENERAL CHASSIS
4-1
EAS1SM9115
TIP
This section is intended for those who have basic knowledge and skill concerning the servicing of
Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.). Those who have little knowl-
edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas-
sembly, or reassembly only by reference to this manual. It may lead to servicing trouble and
mechanical damage.
EAS1SM9116
GENERAL CHASSIS
Removing the seat and side cover
Order Part name Q’ty Remarks
1 Seat 1
2 Air scoop (left) 1
3 Air scoop (right) 1
4 Side cover (left) 1
5 Side cover (right) 1
6 Number plate 1
7 Rear fender 1
For installation, reverse the removal proce-
dure.
4 (2)
75
1
3
6
2
7 Nm (0.7 m•kgf, 5.1 ftIbf)T.R.7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
22 Nm (2.2 mkgf, 16 ftIbf)T.R.
1.3 Nm (0.13 mkgf, 0.94 ftIbf)T.R.16 Nm (1.6 mkgf, 12 ftIbf)T.R.

HANDLEBAR
4-31
EAS1SM9159
HANDLEBAR
Removing the handlebar
Order Part name Q’ty Remarks
Number plate Remove the band only.
1 Clutch cable 1 Disconnect.
2 Clutch lever holder 1
3 Engine stop switch 1
4 Brake master cylinder 1
5 Throttle cable cap 1
6 Throttle cable (pull) 1 Disconnect.
7 Throttle cable (return) 1 Disconnect.
8 Right grip 1
9 Tube guide 1
10 Collars 1
11 Left grip 1
12 Handlebar upper holder 2
13 Handlebar 1

HANDLEBAR
4-34
3. Tighten:
• Lower handlebar holder nut4. Install:
• Handlebar grip “1”
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Slightly coat the handlebar left end with a
rubber adhesive.
b. Install the handlebar grip on the handlebar
by pressing the grip from the left side.
c. Wipe off any excess adhesive with a clean
cloth.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
TIP
Install the handlebar grip to the handlebar so
that the line “a” between the two arrow marks
faces straight upward.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Install:
• Handlebar grip “1”
• Handlebar grip “2”
• Handlebar grip “3”
•Clamp “4”
TIP
• The engine stop switch, the clutch lever, and
the clutch lever holder should be installed ac-
cording to the dimensions shown.
• Pass the engine stop switch lead through the
middle of the clutch lever holder. Lower handlebar holder nut
40 Nm (4.0 m·kgf, 29 ft·lbf)
3
4
T R..
Engine stop switch screw
0.5 Nm (0.05 m·kgf, 0.36 ft·lbf)
Clutch lever holder bolt
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
T R..