Yamaha F40BWHD - Checking the Big-End Oil Clearance

POWR
5-47
CRANKSHAFT AND PISTON
E
CHECKING THE BIG-END OIL
CLEARANCE
NOTE:
Make sure that the crankshaft is qualified
before initiating the following procedure.
1. Measure:
• Big-end oil clearance
Out of specification → Replace the
upper and lower bearings as a set.
NOTE:
• Keep each connecting rod and cap as a
set.
• Measure the big-end 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 and bearing por-
tions of the connecting rod.
(2) Install the upper half of the bearing into
the connecting rod and the lower half
into the connecting rod cap.
NOTE:
Align the projection of the bearing with the
notch in the cap and connecting rod.
(3) Put a piece of Plastigauge
®
onto the
crank pin in parallel to the crankshaft.
(4) Assemble the connecting rod onto the
crank pin.
Big-end oil clearance
0.020 - 0.052 mm
(0.0008 - 0.0020 in)