Yamaha YZ250 2021 User Manual

CHAIN DRIVE
4-32
2. Lubricate:
• Drive chain
3. Install:
• Drive sprocket
• Lock washer
• Drive sprocket nut
NOTICE
ECA14300
Never install a new drive chain onto worn
drive chain sprockets; this will dramatically
shorten the drive chain’s life.
4. Adjust:
• Drive chain slack
Refer to “DRIVE CHAIN SLACK” on page
3-16.
NOTICE
ECA24590
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 swing-
arm or cause an accident. Therefore, keep
the drive chain slack within the specified lim-
its.
EAM30561
INSTALLING THE DRIVE CHAIN (for YZ250X)
1. Install:
• Drive chain
NOTICE
ECA17410
Be sure to put on safety goggles when work-
ing.
TIP
Install the master link with the drive chain cut &
rivet tool. (Use goods on the market.)
a. When press fitting the master link plate
“1”, make sure the space “a” between the
end of the connecting pin “2” and the mas-
ter link plate is 1.2–1.4 mm (0.05–0.06 in).
b. After riveting, make sure the diameter be-
tween the edges “b” of the connecting pin
“2” is 5.5–5.8 mm (0.22–0.23 in).
c. After riveting, make sure the space “c”,
which is inside of the master link “3” and
inside of the master link plate “1”, is 12.1–
12.3 mm (0.476–0.484 in).
Drive sprocket nut
75 N·m (7.5 kgf·m, 55 lb·ft)
Drive chain slack (Maintenance
stand)
48.0–58.0 mm (1.89–2.28 in)
1
2
G089069
3
G089070
New
T
R
.
.

Yamaha YZ250 2021 Specifications

General

Engine Type	249cc liquid-cooled 2-stroke; reed-valve inducted
Bore x Stroke	66.4mm x 72.0mm
Compression Ratio	8.9~10.6:1
Ignition	CDI
Transmission	5-speed; multiplate wet clutch
Final Drive	Chain
Suspension Rear	KYB® single shock; fully adjustable, 12.4-in travel
Brakes Front	Hydraulic disc, 270mm
Tires Front	80/100-21
Tires Rear	110/90-19
Width	32.5 in
Height	50.8 in
Wheelbase	58.5 in
Ground Clearance	14.2 in
Fuel Capacity	2.1 gal
Wet Weight	227 lb
Fuel Delivery	Keihin PWK38S carburetor
Suspension Front	KYB® Speed-Sensitive System inverted fork; fully adjustable, 11.8-in travel
Brakes Rear	Hydraulic disc, 245mm