Checking The Cylinder Body - Yamaha 25BMH Service Manual

POWR
CRANKSHAFT AND CYLINDER BODY
D
1
D
2

CHECKING THE CYLINDER BODY

1. Check:
• Cylinder inner surface
Score mark → Repair/replace.
(use #600 – 800 grit wet sandpaper)
• Water jacket
Mineral deposits/rust/corrosion →
Clean/replace.
CAUTION:
Do not scratch the contacting surfaces of
the crankcase and cylinder head.
2. Check:
• Exhaust passage
Cracks/damage → Replace.
Carbon deposits → Clean.
(use a round scraper)
CAUTION:
Do not scratch the contacting surfaces of
the cylinder and exhaust cover.
3. Measure:
• Cylinder bore "D"
(use a cylinder gauge)
Out of specification → Rebore/replace.
Cylinder gauge
90890-06759
NOTE:
Measure the cylinder bore diameter at three
positions for both D1 and D2. Then, aver-
age the measurement.
5-31
E