Husqvarna 325HDA, Руководство по ремонту

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The crankshaft is journalled in the crankcase on
heavy-duty ball bearings. In addition to the
journalling point for the crankshaft, the crankcase
acts as scavenging pump for the fuel/air mixture
when this is “sucked” from the carburettor and is
forced into the cylinder’s combustion chamber.
The crankcase must be perfectly sealed so as not
to affect this pump function. There cannot be any
leakage either from the crankshaft or between the
crankcase halves or between the crankcase and
the cylinder.
Always replace the sealing rings and gaskets
when servicing the crankcase.
Dismantling
325HS75, 325HS99
Dismantle all components so that only
the crankcase and crankshaft remain.
Now lift the crankshaft out of the
crankcase.
Remove the ball bearing and the
balance cup.
Dismantling
325HS75, 325HS99
See respective sections for detailed
information if necessary.
The bearing has a sliding fit on the
short spindle and a press fit on the long
spindle.
Puller 531 00 48-67 for the bearing with
a press fit.
Assembly
325HS75, 325HS99
Check the crankshaft as set out in the
section “Checking the crankshaft” in the
Workshop Manual.
Clean the contact surfaces on the
crankcase. Lubricate the sealing lips on
the stuffing boxes with a thin layer of
grease.
Fit the balance cup and new bearing on
the crankcase’s short spindle with the
bearing’s open side facing inwards
towards the crank disc.
Punch 502 50 30-13.
Wedge in a shim between the balance
weights, press on the ball bearing on
the long spindle with the stuffing box
turned towards the crank disc. Turn a
little on the outer ring while pressing so
that the stuffing box enters on its collar.
Remove the shim.
Lubricate the big-end bearing with a
few drops of engine oil and position the
crankshaft in the crankcase.
Assemble all the remaining parts in the
reverse order as set out for dismantling.
See respective sections in the Work-
shop Manual.
Leakage test the crankcase according to
the instructions in the Workshop Manual.
Crankshaft and crankcase
The task of the crankshaft is to transfer the recipro-
cating motion of the piston to rotation. To do this
requires a stable design withstanding immense
pressure, rotational and bending strain as well as
high rotational speed. In addition the connecting rod
is exposed to large acceleration and retardation
forces as it moves between top and bottom dead
centres. This puts special demands on the bearings
that must withstand quick changes in load. Besides,
the bearing’s roller retainer also must cope with high
temperatures and friction. Therefore it is extremely
important when servicing, to check the roller retainer
for cracking, wear and discolouration due to over-
heating.
For Husqvarna Parts Call 606-678-9623 or 606-561-4983
www.mymowerparts.com