Checking The Piston Ring Side Clearance; Checking The Piston Pin Boss Bore; Checking The Piston Pin - Yamaha 250GETO Service Manual

POWR
2. Level the piston rings 1 in a cylinder with
a piston crown.
3. Check the piston ring end gap a at the
specified measuring point b. Replace
the piston ring set if out of specification.
a
Piston ring end gap a:
1st :
0.30–0.50 mm
(0.0118–0.0197 in)
2nd :
0.30–0.40 mm
(0.0118–0.0157 in)
Measuring point b: 20 mm (0.79 in)
Checking the piston ring side clear-
ance
1. Measure the piston ring side clearance.
Replace the piston and piston rings as a
set if out of specification.
Piston ring side clearance:
Top ring and 2nd piston ring:
0.02–0.06 mm
(0.0008–0.0024 in)
5-33
Power unit
b
1
1
6F650430
6G450420

Checking the piston pin boss bore

1. Measure the piston pin boss bore.
Replace the piston if out of specification.
Piston pin boss bore:
26.004–26.015 mm
(1.0238–1.0242 in)

Checking the piston pin

1. Measure the piston pin outside diameter.
Replace the piston pin if out of specifica-
tion.
Piston pin diameter:
25.995–26.000 mm
(1.0234–1.0236 in)
6G450430
6S350110
6S35H11