Dismantling; Inspecting The Crankshaft - Husqvarna 326R Workshop Manual

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The task of the crankshaft is to transform the reciprocating motion of the piston to rotation. This requires a
stable design withstanding immense pressure and 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 the top and bottom dead centres. This puts special demands on the bearings that must withstand
quick changes in load. Moreover, the bearing's roller retainer must also cope with high temperatures and
friction. It is therefore extremely important when servicing to check the roller retainer for cracks, wear and
discolouration caused by overheating.
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 a 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 from the crank-
shaft, between the crankcase halves or between the crankcase and the cylinder.
Always replace the sealing rings and gaskets when servicing the crankcase.
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Crankshaft and crankcase

Dismantling

Dismantle all components so that only
the crankcase and crankshaft remain.
Now lift the crankshaft out of the
crankcase.
Inspecting the
crankshaft
Inspect the large end of the connecting
rod.
Inspect the small end of the connecting
rod.
Dismantling
Dismantle all components so that only
the crankcase and crankshaft remain.
See the respective sections for detailed
information if necessary.
Now lift the crankshaft out of the
crankcase.
Remove the bearings (sliding fit).
Remove the gasket residue from the
base of the cylinder and crankcase.
Inspecting the
crankshaft
The crankshaft cannot be reconditioned
but must be replaced if it is worn or
damaged.
Inspect the large end of the connecting
rod. If seizure marks, discolouration on
the sides or damaged needle holders
are found the crankshaft must be
replaced.
Inspect the small end of the connecting
rod.
If seizure marks or discolouration are
found in the bearing track the crank-
shaft must be replaced.