Yamaha MM700A Manual page 109

ENGINE
NOTE
cations, it is possible to buy and install new
standardsizepistons without reboring. New
pistons will take up some of the excessive
piston-to-cylinder clearance. However, do
not install new standard size pistons in a
cylinder that is worn past the wear limit.
7. If the cylinder bore is not worn past the service limit,
check the bore carefully for scratches or gouges. Inspect
the hardened surface of the cylinder bore for damage and
bits of aluminum (from the piston) stuck to the cylinder
bore.
8. Check all threaded holes in the cylinder for thread
damage. Minor damage can be cleaned up with a suitable
metric tap. Refer to Chapter One for information pertain-
ing to threads, fasteners and repair tools. If damage is ex-
cessive, install a thread insert.
9. Check the cylinder base studs for looseness, stripping
or other damage. If necessary, replace studs as described
in Chapter One.
10. Check the top surface of the cylinder.
appears warped, scratched or corroded, resurface the cyl-
inder lightly as follows.
a. Remove the cylinder head studs as described in
(Figure 18).
ure-eight pattern on the sandpaper.
d. Rotate the cylinder several times to avoid removing
too much material from one side.
Chapter One.
11. After servicing the cylinder, wash the bore with hot,
soapy water. This is the only way to clean the fine grit ma-
terial left from the bore or honing job from the cylinder
wall. After washing, run a clean white cloth through the
cylinder. The white cloth should show no traces of grit or
other debris. If the white cloth test indicates the cylinder is
still dirty, rewash the cylinder wall. After thoroughly
cleaning the cylinder, lubricate the cylinder wall with
clean engine oil.
Installation
1. If removed, install the six hollow dowel pins (two per
cylinder) into the crankcase (Figure 20).
2. Clean the cylinder bore as described under Inspection
in this chapter.
3. Make sure the top surface of the crankcase and the bot-
tom cylinder surface are clean before installation.
Refer to Figure 21 and install the new cylinder base
4.
gasket. The tab must be toward the flywheel end of the
crankcase.
If the surface
Chapter One.
onto a piece of thick plate glass or surface plate
NOTE
Check the pistons to be sure the piston pin
clips (Figure 22) are installed and correctly
positioned so the gap is down.
103