Yamaha MTN850-A 2017 Service Manual page 303

TIP
To install the big end bearing, care should be
taken not to install it at an angle and the position
should not be out of alignment.
a
a. Side machined face
b. Thrusting faces
e. Loosen the connecting rod bolt, remove the
connecting rod and connecting rod cap and
install these parts to the crankshaft with the
big end bearing kept in the current condition.
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3. Install:
• Oil ring expander "1"
• Lower oil ring rail "2"
• Upper oil ring rail "3"
• 2nd ring "4"
• Top ring "5"
(into the piston)
TIP
Be sure to install the piston rings so that the
manufacturer's marks or numbers "a" face up.
4. Install:
• Piston "1"
(onto the respective connecting rod "2")
• Piston pin "3"
• Piston pin clips "4"
TIP
• Apply engine oil onto the piston pin.
• Make sure that the "Y" mark "a" on the connect-
ing rod faces left when the punch mark "b" on
the piston is pointing up as shown.
b
New
CONNECTING RODS AND PISTONS
• Install the piston pin clips, so that the clip ends
are 3 mm (0.12 in) "c" or more from the cutout
in the piston.
• Reinstall each piston into its original cylinder.
2
4
5. Lubricate:
• Piston
• Piston rings
• Cylinder
(with the recommended lubricant)
Recommended lubricant
6. Offset:
• Piston ring end gaps
a. Top ring
b. 2nd ring
c. Upper oil ring rail
d. Oil ring expander
e. Lower oil ring rail
A. Exhaust side
5-68
a
3
4
Engine oil
90˚
b,e c
a,d
45˚
b
1
c
90˚