Husqvarna 241R Workshop Manual page 51

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 retarda-
tion 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 journal-
ling 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 lea-
kage 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.
50
Crankshaft and crankcase
Dismantling
Dismantle all components so that only the
crankcase and crankshaft remain.
502 50 18-01
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 4 screws holding the crank-
case halves together.
Separate the crankcase halves (a special
tool is not required).
The crankshaft has a snug fi t in the
crankshaft bearing.
NOTE!
Note the guide sleeves between
the crankcase halves so they are
not lost!
Lift out the crankshaft out of the clutch
side's crankcase half (a special tool is not
required).
Remove the crankcase gasket.