Yamaha TZ125M1 Owner's Service Manual page 108

CYLINDER HEAD, CYLINDER AND PISTON
2. Inspect:
• Cylinder head water jacket
Crust of minerals/Rust ≥ Remove.
• Cylinder head contact surface
Wear/Damage ≥ Replace.
• Recess of insert portion a
The contact surface b of the insert portion
is recessed below the aluminum portion c
≥ Replace.
EC474210
Cylinder
1. Remove:
• Carbon deposits
Use a rounded scraper 1.
NOTE:
Do not use a sharp instrument. Avoid scratch-
ing the aluminum.
2. Inspect:
• Cylinder inner surface
Score marks ≥ Repair or replace.
Use #400~600 grit wet sandpaper.
C C CAUTION:
Do not rebore the cylinder.
3. Inspect:
• Travel distance for cylinder
3,000 km (1,800 miles) or more≥ Replace.
EC474313
Piston
1. Inspect:
• Piston crown
Damage and crack due to detonation≥Replace.
• Piston pin hole
Crack≥ Replace.
• Contact with cylinder
Excessive scuffing, score a ≥ Use
#400~600 grit wet sandpaper in a criss-
cross manner b.
• Heat discoloration≥ Replace.
4-20
ENG