Inspection - Yamaha RS90GTZ Service Manual

CONNECTING RODS AND PISTONS
5-67

INSPECTION

1. Inspect:
• Piston wall
• Cylinder wall
Vertical scratches → Replace the crank-
case, and replace the piston and piston
rings as a set.
2. Measure:
• Piston-to-cylinder clearance
Measurement steps:
1st step:
• Measure cylinder bore "C" with the cylinder
bore gauge .
TIP
Measure cylinder bore "C" by taking side-to-
side and front-to-back measurements of the
cylinder.
Then, find the average of the measurements.
Cylinder bore "C"
Taper limit "T"
Out of round "R"
"C" = maximum of D
"T" = maximum of D
maximum of D or D
5
"R" = maximum of D
maximum of D D or D
2 4
• If out of specification, replace the crankcase,
and the piston and piston rings as a set.
ENG
82.000 ~ 82.010 mm
(3.2283 ~ 3.2287 in)
0.050 mm (0.0020 in)
0.050 mm (0.0020 in)
~ D
1 6
or D –
1 2
6
D or D –
1 3 5
6