Yamaha ttr230 Service Manual page 130

INSPECTION AND REPAIR
3. Check:
• Cylinder liner
Wear/scratches => Replace or buff.
4. Measure:
• Cylinder – piston clearance
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Measurement steps:
• Measure the cylinder diameter "C" using
a suitable instrument.
a 40 mm from the top of the cylinder.
NOTE:
Measure the cylinder diameter "C" at
various points 40 mm from the top of the
cylinder and determine the measurement
average.
• If out of specification, grind or replace
cylinder, piston, and rings.
• Measure the lower end diameter of the
piston "P" using a micrometer.
b 4.0 mm.
• If out of specification, replace piston and
rings.
4-36
ENGINE
Cylinder diameter "C":
69.970~70.020 mm
<limit>: 70.1 mm
C=(X+Y)/2
Piston skirt diameter "P":
69.925~69.975 mm