Piston. Piston Pin, And Piston Rings - Yamaha MM700A Manual

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5. Make sure the end gaps of the piston rings are aligned
with the locating pins in the ring grooves (Figure 23). Lu-
bricate the piston rings and the inside of each cylinder
bore lightly with injection oil.
6. Place a piston holding tool or a wooden block
24) under one piston and turn the crankshaft until the pis-
ton is down firmly against the tool. This makes cylinder
installation easier.
NOTE
When reinstalling the same cylinders, make
sure to install the cylinder previously
7. Align the cylinder with the piston so the exhaust port
will face toward the front of the engine. Install the cylin-
der, compressing each piston ring by hand as the cylinder
slides over it. When both rings are in the cylinder, slide the
cylinder down and remove the piston holding tool. Slide
the cylinder all the way down against the gasket and
crankcase. Make sure the base of the cylinder is fully
seated against the crankcase.
8. Repeat the procedure to install the other cylinders.
I ighten the cylinder retaining nuts in a crossing pattern to
28 N*m (20 ft.-lb.).
9. Install the carburetor assembly as described in Chapter
Five.
Tighten the exhaust manifold retaining bolts in a crossing
pattern to 27 N m (20 fi.-lb.).
fler and exhaust pipe as described in Chapter Five.
13. If new components were installed or if the cylinders
were bored or honed, the engine must be broken-in as if it
were new. Refer to Break-In Procedure in Chapter Three.
(Figure
The piston is made of an aluminum alloy. The piston pin
is a precision fit and is held in place by a clip at each end.
A caged needle bearing is used on the small end of the
connecting rod. See Figure 12.
Piston and Piston Ring Removal
1. Remove the cylinder head and cylinder as described in
this chapter.
The pistons are marked with an arrow cast
on the top of the crown pointing to the ex-
haust port.
2. Identify the pistons and cylinders by marking on the
tops of the pistons the letters PTO (left side), MAG (right
side) or CEN (middle). In addition, keep each piston to-
CHAPTER FOUR
PISTON, PISTON PIN,
AND PISTON RINGS
NOTE