Yamaha MT-09 2021 - Checking the Balancer Shaft

5-83
CRANKSHAFT AND BALANCER SHAFT
EAS31076
CHECKING THE BALANCER SHAFT
1. Measure:
• Balancer shaft runout
Out of specification → Replace the balancer
shaft.
2. Check:
• Balancer shaft journal surfaces
• Bearing surfaces
Scratches/wear → Replace the balancer
shaft.
3. Measure:
• Balancer shaft journal-to-balancer shaft bear-
ing clearance
Out of specification → Replace the balancer
shaft journal bearings.
NOTICE
ECA18400
Do not interchange the balancer shaft jour-
nal bearings. To obtain the correct balancer
shaft-journal-to-balancer shaft-journal-bear-
ing clearance and prevent engine damage,
the balancer shaft journal bearings must be
installed in their original positions.
a. Clean the balancer shaft journal bearings,
balancer shaft journals, and bearing por-
tions of the crankcase.
b. Place the upper crankcase upside down on
a bench.
c. Install the balancer shaft journal upper
bearings “1” and the balancer shaft into the
upper crankcase.
TIP
Align the projections “a” on the balancer shaft
journal upper bearings with the notches “b” in the
upper crankcase.
d. Put a piece of Plastigauge® “1” on each
balancer shaft journal.
TIP
Do not put the Plastigauge® over the oil hole in
the balancer shaft journal.
e. Install the balancer shaft journal lower bear-
ings “1” into the lower crankcase and as-
semble the crankcase halves.
TIP
• Align the projections “a” of the balancer shaft
journal lower bearings with the notches “b” in
the crankcase.
• Do not move the balancer shaft until the clear-
ance measurement has been completed.
Balancer shaft runout limit
0.030 mm (0.0012 in)
Balancer shaft journal to balanc-
er shaft bearing clearance
0.023–0.047 mm (0.0009–0.0019
in)
J 1 J 2 J 3 J 4
B
1
a
b
G089019
1