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Yamaha WR250F 2022 User Manual

Yamaha WR250F 2022
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CYLINDER HEAD
5-22
EAM30086
REMOVING THE CYLINDER HEAD
1. Remove:
Cylinder head bolt and nut
TIP
Loosen the bolts in the proper sequence as
shown.
Loosen each bolt 1/2 of a turn at a time. After
fully loosening all the bolts, remove them.
M9 135 mm (5.31 in): [4], [5], [6]
M9 145 mm (5.71 in): [3]
EAM30087
CHECKING THE TIMING CHAIN GUIDE
(INTAKE SIDE)
1. Check:
Timing chain guide (intake side)
Damage/wear Replace.
EAM30088
CHECKING THE CYLINDER HEAD
1. Eliminate:
Combustion chamber carbon deposits
TIP
Use a rounded scraper, not a sharp instrument,
in order not to damage or scratch the spark plug
bore threads.
2. Check:
Cylinder head
Damage/scratches Replace.
TIP
When replacing the cylinder head, replace also
the valve.
Refer to “CHECKING THE VALVE SEATS” on
page 5-28.
Cylinder head coolant passages
Mineral deposits/rust Eliminate.
3. Measure:
Cylinder head warpage
Out of specification Resurface the cylinder
head.
a. Place a straightedge and a thickness
gauge across the cylinder head.
b. Measure the warpage.
c. If the limit is exceeded, resurface the cylin-
der head as follows.
d. Place a 400–600 grit wet sandpaper on a
surface plate, and resurface the cylinder
head using a figure-eight sanding pattern.
TIP
To ensure an even surface, turn the cylinder
head several times.
EAM30089
INSTALLING THE CYLINDER HEAD
1. Install:
Timing chain guide (intake side) “1”
Dowel pin “2”
Cylinder head gasket “3”
Cylinder head “4”
TIP
While pulling up the timing chain, install the
timing chain guide (intake side) and the cylin-
der head.
Install the cylinder head gasket as shown in the
illustration.
x2 x3 x1
FWD
6
1
2
3
5
4
6
1
2
3
5
4
Warpage limit
0.05 mm (0.0020 in)
New

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Yamaha WR250F 2022 Specifications

General IconGeneral
Bore x Stroke77.0mm x 53.6mm
Compression Ratio13.8:1
IgnitionTCI: Transistor Controlled Ignition
Final DriveChain
Suspension RearKYB® single shock; fully adjustable, 12.5-in travel
Length85.6 in
Width32.5 in
Height50.0 in
Seat Height38.2 in
Wheelbase58.3 in
Rake (Caster Angle)27.2°
Trail4.6 in
Fuel Capacity2.2 gal
Wet Weight254 lb
Engine TypeLiquid-cooled, DOHC, 4-stroke
Fuel DeliveryFuel injection
Suspension FrontKYB® Speed-Sensitive System inverted fork; fully adjustable
Brakes FrontHydraulic single disc
Brakes RearHydraulic single disc brake
Tires Front80/100-21
Tires Rear110/100-18

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