Yamaha JT1 Series Service Manual page 46

ENGINE·
Crankshaft
A. Removing the Crankshaft Assembly
Remove the crankshaft assembly with the crankcase
separating tool.
Note: Fully tighten the bolts of the crankcase dividing
tool. and keep the too! parallel with the crankcase
surface.
F,g 3-17-3
B. Installing the Crankshaft Assembly
Install the crankshaft by using the crankshaft httmg
tooL Take care not to allow the connecting rod to
contact the crankcase For this.hold the piston at top-
dead -center and turn the handle. then tighten the bolt
of the special tool
C. Inspection and Servicing
1) Checking the crankshaft components
F,g 3-17·4
Check connecting rod axial play at
Small end play should not exceed
the small end (to determine the amount 2 mm. (0.078 in.)
of wear of crank pin and bearing at
large end)(F1g 3-17-5)
Check accuracy of the crankshaft
Dial gauge readings should be
ass y runout. (M isalignmenl of parts within 0.03 mm. (0.0012 in.)
of the crankshaft)(F1g 3-17-6)
F,g. 3-17-5
- 4 0 -
If small end play exceeds 2 mm, disassemble
the crankshaft. check connecting rod crank
pin and large end bearing. Replace defective
parts. Small end play after reassembly should
be within 0.8~1.0 mm.(0.031~0.04 in.)
Correct
.,,
misalignment by tapping the
flywheel with a brass hammer and by using a
wedge.
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Fig 3-17-6
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