Yamaha YFM660 01 User Manual

5 - 61
ENGSHIFT SHAFT
INSTALLING THE SHIFT SHAFT
1.Install:

Roller 1
 

Collar

Shift shaft spring

Shift shaft 2
 
NOTE:

Install the end of the shift shaft spring onto
the shift shaft spring stopper 3
.

Install the end of the shift shaft lever onto the
roller 1
.
2.Install:

Shift arm 1
 

Bolt 2
 
NOTE:
Be sure to install the shaft arm so that position
a
 is horizontal.
T R..10 Nm (1.0 m  kg, 7.2 ft  lb) 

5 - 62
ENGCRANKCASE
CRANKCASE
TIMING CHAIN AND SPEED SENSOR ROTOR
Order Job name/Part name Q’ty Remarks
Removing the timing chain and 
speed sensor rotor Remove the parts in the order below.
Engine assembly Refer to “ENGINE REMOVAL”.
Cylinder head cover Refer to “CYLINDER HEAD COVER”.
Cylinder head Refer to “CAMSHAFT AND CYLINDER 
HEAD”.
Cylinder and piston Refer to “CYLINDER AND PISTON”.
AC rotor Refer to “AC MAGNETO”.
Clutch, balancer drive gear and bal-
ancer driven gearRefer to “CLUTCH”.
Oil pump...

5 - 63
ENGCRANKCASE
Order Job name/Part name Q’ty Remarks
3 Reverse shift lever 1
4 Reverse shift lever spring 1
5 Circlip 1
6 Neutral switch 1
7 Reverse switch 1
8 Oil pipe joint 1
9 Circlip 1
10 Wave washer 1
11 Speed sensor rotor 1
12 Circlip 1
For installation, reverse the removal pro-
cedure. 

5 - 64
ENGCRANKCASE
CRANKCASE
Order Job name/Part name Q’ty Remarks
Separating the crankcase
Remove the parts in the order below.
1 Right crankcase 1
Refer to “CRANKCASE”. 2 Dowel pin 2
3 Dowel pin/O-ring 1/1
4 Left crankcase 1
5 Oil strainer 1
6 Cover 1
7 Oil strainer gasket 1
For installation, reverse the removal pro-
cedure. 

5 - 65
ENGCRANKCASE
CRANKCASE BEARING
Order Job name/Part name Q’ty Remarks
Removing the crankcase bearing
Remove the parts in the order below.
Crankshaft and balancer Refer to “CRANKSHAFT AND BAL-
ANCER”.
Transmission Refer to “TRANSMISSION”.
1 Oil seal retainer 1
2 Oil seal 3
3 Bearing retainer 3
4 Bearing 8
For installation, reverse the removal pro-
cedure. 

5 - 66
ENGCRANKCASE
SEPARATING THE CRANKCASE
1.Separate:

Left crankcase 

Right crankcase
***********************************************
Separation steps:

Remove the crankcase bolts.
NOTE:

Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove
them.

Loosen the bolts in stages, using a criss-
cross pattern.
ÈLeft crankcase 
ÉRight crankcase

Remove the right crankcase.
CAUTION:
Use a soft hammer to tap on one side of the
crankcase. Tap only on reinforced portions
of the...

5 - 67
ENGCRANKCASE
CHECKING THE CRANKCASE
1.Thoroughly wash the case halves in a mild
solvent. 
2.Clean all the gasket mating surfaces and
crankcase mating surfaces thoroughly.
3.Check:

Crankcase 
Cracks/damage →
 Replace.

Oil delivery passages
Clogged →
 Blow out with compressed air.
CHECKING THE BEARINGS
1.Check: 

Bearing
Clean and lubricate, then rotate the inner
race with a finger.
Roughness →
 Replace.
ASSEMBLING THE CRANKCASE
1.Apply:

Sealant (Quick Gasket®) 1
 
(to the mating surfaces of both...

5 - 68
ENGCRANKCASE
3.Fit the right crankcase onto the left crank-
case. Tap lightly on the case with a soft ham-
mer.
CAUTION:
Before installing and torquing the crank-
case holding bolts, be sure to check
whether the transmission is functioning
properly by manually rotating the shift cam
in both directions.
4.Install:

Lead guides 1
 

Hose guide 2
 

Crankcase bolts
5.Tighten:

Crankcase bolts
(follow the proper tightening sequence)
ÈRight crankcase
ÉLeft crankcase
3Bolt:   = 30 mm
4Bolt:   = 45 mm...

5 - 69
ENGCRANKSHAFT AND BALANCER
CRANKSHAFT AND BALANCER
Order Job name/Part name Q’ty Remarks
Removing the crankshaft and bal-
ancerRemove the parts in the order below.
Crankcase Separate. Refer to “CRANKCASE”.
1 Balancer 1
2 Crankshaft 1 Refer to “REMOVING/INSTALLING THE 
CRANKSHAFT”.
For installation, reverse the removal pro-
cedure. 

5 - 70
ENGCRANKSHAFT AND BALANCER
REMOVING THE CRANKSHAFT
1.Remove:

Crankshaft
Use a crankcase separating tool 1
.
Crankcase separating tool:
P/N. YU-01135-A, 90890-01135
CHECKING THE CRANKSHAFT
1.Measure:

Crank width A
 
Out of specification →
 Replace the crank-
shaft.

Side clearance D
 
Out of specification →
 Replace the crank-
shaft.

Runout C
 
Out of specification →
 Replace the crank-
shaft.
***********************************************
Crankshaft reassembling point:
The crankshaft 1
 and...