Husqvarna 343R, 345RX, 343F, 345FX, 345FXT manual Crankshaft and crankcase, Dismantling

7	Crankshaft and crankcase
The task of the crankshaft is to transform the reciprocating		The crankshaft is journalled in the crankcase on
motion of the piston to rotation. This requires a stable		heavy-duty ball bearings. In addition to the journalling
design withstanding immense pressure and rotational and		point for the crankshaft, the crankcase acts as a
bending strain, as well as high rotational speed. In addition		scavenging pump for the fuel/air mixture when this is
the connecting rod is exposed to large acceleration and		“sucked” from the carburettor and is forced into the
retardation forces as it moves between the top and bottom		cylinder’s combustion chamber. The crankcase must
dead centres. This puts special demands on the bearings		be perfectly sealed so as not to affect this pump
that must withstand quick changes in load. Moreover, the		function. There cannot be any leakage from the crank-
bearing’s roller retainer must also cope with high tempera-		shaft, between the crankcase halves or between the
tures and friction. It is therefore extremely important when		crankcase and the cylinder.
servicing to check the roller retainer for cracks, wear and		Always replace the sealing rings and gaskets when
discolouration caused by overheating.		servicing the crankcase.

Dismantling

Dismantle all components so that only the crankcase and crankshaft remain.

Dismantle the guard under the crank- case.

Bend away the heat guard (A) and cable guide (B).

Dismantling

Dismantle all components so that only the crankcase and crankshaft remain.

See the respective sections for detailed information if necessary.

Remove the 4 bolts and lift off the guard from under the crankcase.

Bend away the heat guard (A) with your fingers and carefully push the cable guide (B) aside with a screwdriver.

52

Remove the 4 bolts holding the crank- case halves together.

502 50 18-01

Remove the 4 bolts holding the crank- case halves together.