Yamaha YZ250N Owner's Service Manual page 260

CYLINDER HEAD, CYLINDER AND PISTON
3. Combination:
Combine the piston and cylinder by the fol-
lowing chart.
Cylinder mark
A
B
C
D
NOTE:
When you purchase a cylinder, you cannot des-
ignate its size. Choose the piston that matches
the above chart.
EC474840
Power valve
1. Inspect:
9Power valve 1, 2 1
Wear/Damage
Carbon deposits
9Link lever 2
9Pulley 3
9Valve shaft 4
9Link rod 5
9Plain washer 6
Wear/Damage
9Spring 1, 2 7
Broken Replace.
EC474901
Power valve hole on cylinder
1. Remove:
9Carbon deposits
From power valve hole surface a.
NOTE:
Do not use a sharp instrument. Avoid scratching
the aluminum.
4-25
ENG
Piston mark (color)
A (red)
B (orange)
C (green)
D (purple)
Replace.
Remove.
Replace.