Yamaha YZ250 2021 Owner's Manual page 32

Gear ratio
1st
2nd
3rd
4th
5th
Secondary reduction ratio
Final drive
Air filter
Air filter element
Air filter oil grade
Carburetor
Type  quantity
ID mark
Main jet
Main air jet
Jet needle
Needle jet
Cutaway
Pilot outlet
Pilot jet
Bypass 1
Air screw turns out
Valve seat size
Starter jet 1
Power Jet
Float height
Throttle grip free play
ENGINE SPECIFICATIONS
1.929 (27/14)
1.533 (23/15)
1.278 (23/18) (YZ250)
1.313 (21/16) (YZ250X)
1.050 (21/20) (YZ250X)
1.091 (24/22) (YZ250)
0.840 (21/25) (YZ250X)
0.952 (20/21) (YZ250)
3.571 (50/14)
Chain
Wet element
Yamaha foam air filter oil or other quality foam
air filter oil
PWK38  1
1P87 50
#178
#200
N3-EW-2
ø2.9(#6)
#7
0.8
#50
1.5
1-1/4
3.8
#85
#50
6.5 mm (0.26 in)
3.0–5.0 mm (0.12–0.20 in)
2-3