Yamaha YZ250 2021 User Manual

ENGINE
8-5
EAM30599
CARBURETOR SETTING PARTS
Part name Size Part number
Main jet “1” Rich #190 4MX-14943-45
#188 4MX-14943-95
#185 4MX-14943-44
#182 4MX-14943-94
#180 4MX-14943-43
(STD) #178 4MX-14943-93
#175 4MX-14943-42
#172 4MX-14943-92
#170 4MX-14943-41
#168 4MX-14943-91
#165 4MX-14943-40
Lean #162 4MX-14943-90
Pilot jet “2” Rich #62 4MX-14948-12
#60 4MX-14948-11
#58 4MX-14948-10
#55 4MX-14948-09
#52 4MX-14948-08
(STD) #50 4MX-14948-07
#48 4MX-14948-06
#45 4MX-14948-05
#42 4MX-14948-04
#40 4MX-14948-03
Lean #38 4MX-14948-02
Jet needle
“3”
Rich N8RH 4SR-14916-RH
N3EH 4SR-14916-EH
N8RW 4SR-14916-RW
(STD) N3EW 4SR-14916-EW
N3CW 4SR-14916-CW
N3EJ 4SR-14916-EJ
Lean N3CJ 4SR-14916-CJ
Power Jet
“4”
Rich #65 4JT-1494F-13
#60 4JT-1494F-11
#55 4JT-1494F-09
(STD) #50 4JT-1494F-07
Lean #40 4JT-1494F-03

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