Husqvarna 122C Workshop Manual page 48

7
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 bet-
ween 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 discoloura-
tion 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 crankshaft,
between the crankcase halves or between the crankcase and the cylinder.
Always replace the sealing rings and gaskets when servicing the crankcase.
46
Crankshaft and crankcase
Dismantling
Dismantle all components so that only
the crankcase and crankshaft remain.
502 71 27-02
Separate the crankcase halves.
Lift out the crankshaft.
Remove the crankcase gasket.
Dismantling
Dismantle all components so that only
the crankcase and crankshaft remain.
See the respective sections for detailed
information if necessary.
Dismantle the 3 screws holding the
crankcase halves together.
Separate the crankcase halves (a spe-
cial tool is not required).
The crankshaft has a snug fi t in the
crankshaft bearing.
Lift out the crankshaft out of the clutch
side's crankcase half (a special tool is
not required).
Remove the crankcase gasket.