Yamaha YZ250 2021 User Manual

STARTING AND BREAK-IN
1-12
of cables, free play of the brake, stretch of the
drive chain, looseness of the spoke, and so
on.
NOTICE
ECA25821
After a break-in or after each race, always
check the points shown in “TORQUE-
CHECK POINTS” for tightening torques and
retighten them.
Also when the following parts are replaced, a
break-in is required.
• Cylinder and Crankshaft: A break-in is re-
quired for about an hour.
• Piston, Piston ring, Valve, Camshaft, and
Gear: A break-in is required for about 30
minutes at a throttle opening of 1/2 or less.
Observe the condition of the engine carefully
during a break-in.
For checkpoints for a break-in, see “MAIN-
TENANCE AFTER BREAK-IN”. If any prob-
lem is found, immediately stop the engine
and make a checkup.

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