ENG
CYLINDER AND PISTON
CHECKING THE PISTON RINGS
1. Measure:
• piston ring side clearance
Out of specification
-->
Replace the piston
and piston rings as a set.
Before measuring the piston ring side clearance,
eliminate any carbon deposits from the piston ring
grooves and piston rings.
Piston ring side clearance
Compression ring
0.030 ~ 0.065 mm
(0.0011 ~ 0.0026 in)
<limit>: 0.10 mm (0.004 in)
Scratcher ring
0.020 ~ 0.055 mm
(0.0008 ~0.0022 in)
<limit>:0.10mm (0.004 in)
NOTE:
2. Install:
• ring (inside the cylinder)
Level the piston ring into the cylinder with the
piston sprocket.
a
40mm
3. Measure:
•
piston ring end gap
Out of specification
-->
Replace.
The oil ring expander spacer’s end gap cannot
be measured. If the oil ring rail’s gap is excessive,
replace all three piston rings as a set.
Piston ring end gap
Compression ring
0.19 ~ 0.31 mm
(0.0075 ~0.0122 in)
<limit>: 0.60 mm (0.0236 in)
Scratcher ring
0.30 ~ 0.45 mm
(0.0118 ~ 0.0177 in)
<limit>: 0.60 mm (0.0236 in)
Oil ring
0.10 ~ 0.35 mm
(0.004 ~ 0.0137 in)
NOTE:
NOTE:
a
5-33
Summary of Contents for YBR250 2007
Page 1: ...YBR250 SERVICE MANUAL 5D1 F8197 E0 2007 ...
Page 2: ......
Page 359: ...YAMAHA MOTOR DA AMAZÔNIA LTDA ...
