Husqvarna 226R, Workshop Manual

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Crankshaft and crankcase
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 aff ect 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.
Dismantling
Dismantle all components so that only the
crankcase and crankshaft remain.
Remove the 4 crankcase screws.
Dismantling
Dismantle all components so that only the
crankcase and crankshaft remain.
See the respective sections for detailed
information if necessary.
Remove the key for the fl ywheel.
Dismantle the 4 screws holding the crank-
case halves together.
Separate the crankcase halves. Separate the crankcase halves (a special
tool is not required).
The crankshaft has a snug fi t in the
crankshaft bearing.
Lift out the crankshaft.
Remove the crankcase gasket.
Lift the crankshaft out of the crankcase
half on the starter side (a special tool is
not required).
Remove the crankcase gasket.