Yamaha Fazer, Service Manual

Page: 96 / 213

ENG
ENGINE INSPECTION AND REPAIR
4-22
CYLINDER AND PISTONS
1. Inspect :
• Cylinder and Piston walls
Vertical scratches Ÿ Rebore or replace
the Cylinder and the Piston
2. Measure :
• Piston-to-Cylinder clearance
ææææææææææææææææææææææææææææææææææ
Measurement steps :
1st step :
• Measure the Cylinder Bore “C” with a Cylin-
der Bore Gauge.
NOTE :
Measure the Cylinder Bore “C” in parallel to and
at right angles to the Crankshaft. Then, find the
average of the measurements.
• If out of specification, rebore or replace the
Cylinder- Piston Kit
2nd step :
• Measure the Piston Skirt diameter “P” with a
Micrometer.
ç 4.5 mm from the Piston bottom edge
• If out of specification, replace the Piston and
the Piston Rings as a set.
3rd step:
• Calculate the Piston-to Cylinder clearance us-
ing the following formula :
• If out of specification, rebore or replace the
Cylinder, and replace the Piston and Piston
Rings as a set
ææææææææææææææææææææææææææææææææææ
Piston-to-Cylinder clearance = Cylinder
Bore “C”– Piston Skirt diameter “P”
“C”=Maximum Diameter D
“T” =(Maximum D1 or D2) - (Maximum D5 or D6)
“R”=(Maximum D1, D3 or D5)
- (Maximum D2, D4 or D6)
Piston-to-Cylinder clearance :
0.020 ~ 0.027 mm
Cylinder Bore “C”
Taper limit “T”
Out of round “R”
54.000 ~ 54.018 mm
0.005 mm
0.01 mm
Piston size p
Standard 53.977 ~ 53.996 mm
Oversize
Ist
II nd
P
ç