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ENGINE CHECKS AND ASSEMBLY
3.4 GEAR UNIT: CHECKS AND
REASSEMBLY
The gearbox unit is made up of the gearshift and of
the gearbox itself. The gearshift in its turn is divided
into external and internal gearshift.
The checks and procedures for inspecting and
reassembling these units to the engine are set out
below.
3.4.1 GEARBOX UNIT CHECK
Use protective jaws to clamp the main shaft and
secondary shaft.
Use a thickness gauge to check the axial play be-
tween the gearshift forks and the gearwheels. The
measured play must not exceed the service limit
indicated below:
service limit: 0.5mm
If the measured axial play is greater, before re-
placing either the gearwheels or the forks, check
the state of wear of the latter (par. 3.4.4)
Remove the various elements and check that:
• the support surfaces of the main shaft and sec-
ondary shaft show no abnormal wear or signs
of seizure;
• the sides of the teeth are free from chipping or
abnormal wear;
• the sliding areas of the gearwheels show no ab-
normal wear or traces of seizure;
• the front claw clutches of the gearwheels are
not chipped or rounded;
• the roller bearings are intact and efficient;
• none of the thrust washers show traces of ab-
normal wear or meshing.
Should any of these defects be found, replace the
concerned parts.
Check of wear of forks and gearwheels.
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