TM 5-4320-302-14
6-20. CRANKSHAFT ASSEMBLY (CONT)
Location/Item
Action
Remarks
12. Crankshaft
Replacement of main bearing bush depends on
main bearing
diameter of crankshaft main bearing journal.
journal and
Measure journal diameter in accordance with
main bearing
paragraph 6-18.
bush
13. Radial clear-
Determine main bearing bush/crankshaft main
ance
bearing journal radial clearance by subtracting
journal diameter from bearing bush bore. Clear-
ance should be 0.0024 to 0.0046 inch (0.060 to
0.118 mm). Maximum allowable clearance is
0.0118 inch (0.3 mm). Make sure radial clear-
ance is within tolerance limits. If not, recheck
bearing bush, crankshaft, and/or crankcase. Re-
place components in that order if necessary
until radial clearance falls within tolerance
limits.
14. Main bearing
Measure distance that bush extends from crank-
bush end
case. This measurement is the main bearing bush
clearance
end clearance. It should be 0.0551 to 0.0669
inch (1.40 to 1.70 mm). If measurement is not
within these tolerance limits, bush is either worn
down or protrudes too far from crankcase and
must be replaced.
6-170
