Yamaha MX-800, Service Manual

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ENGINE
PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT
INSTALLING THE CRANKCASE COVER 1
1.
Install:
• Crankcase cover 1
• Crankcase cover 1 bolts “1” to “8”
TIP
Tighten the bolts to the specified torque in two steps and in
order from “1” to “8”.
CHECKING THE CYLINDERS AND PISTONS
The following procedure applies to all of the pistons and
cylinders.
1.
Check:
• Piston wall
• Cylinder wall
Vertical scratches

Replace the cylinder, and
replace the piston and piston rings as a set.
2.
Measure:
• Cylinder warpage
TIP
Measure the warpage on the contact surface of the cylin-
der head at six points using a straight edge and feeler
gauge set.
Out of specification

Replace the crankcase
assembly.
3.
Measure:
• Piston-to-cylinder clearance
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure cylinder bore “C” with the cylinder bore
gauge.
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8
8
Crankcase cover 1 bolt:
1st: 12 N·m (1.2 kgf·m, 8.7 lb·ft)
2nd: 30 N·m (3.0 kgf·m, 22 lb·ft)
T
R
.
.
Feeler gauge set:
YU-26900-9
Warpage limit:
0.05 mm (0.002 in)