Checking The Main-Bearing Oil Clearance - Yamaha F40BMHD Wartungshandbuch

POWR
a
CRANKSHAFT AND PISTON
3
2
1
CHECKING THE MAIN-BEARING OIL
CLEARANCE
NOTE:
Make sure that the crankshaft is qualified
before initiating the following procedure.
1. Measure:
• Main-bearing oil clearance
Out of specification → Replace the
upper and lower bearings as a set.
Main-bearing oil clearance
0.012 - 0.044 mm
(0.0005 - 0.0017 in)
NOTE:
Measure the main-bearing oil clearance at
room temperature (20 °C (68 °F)).
Measuring steps
CAUTION:
Install the bearings in their original posi-
tions. Incorrect oil clearance measure-
ments can lead to engine damage.
(1) Clean the bearings, main journals, and
bearing portions of the crankcase and
cylinder block.
(2) Place the cylinder block upside down
on a bench.
(3) Install half of the bearings
crankshaft
3
.
NOTE:
Align the projection
the notch in the cylinder body.
(4) Put a piece of Plastigauge
main journal in parallel to the crank-
shaft.
NOTE:
Do not put the Plastigauge
hole in the main journal of the crankshaft.
5-45
1
2
into the cylinder block
a
of the bearing with
®
on each
®
over the oil
E
and the