Chainsaw Repair

Husqvarna 50 service bulletin

MODEL: 50 SPECIAL REPLACES 50 RANCHER FROM SERIAL NUMBER 9190006
The differences between the model 50 S and 50 R are among other things that the displacement is increased from 49 cm3 to 51 cm3 and that the SA-silencer is replaced. Due to the changes above, the 50 Special has gone through a for each country new specific testing procedure. This means that no 51 cm3 cylinders should be mounted on saws with lower serial number than 9190006.
The 51 cm3 cylinder base does not fit the crankcases of older 50 R models.
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The 51 cm3 cylinder base has the outer diameter of approx. 49,7 mm (the outer diameter of the piston = 45 mm).
The 49 cm3 cylinder base has the outer diameter of approx. 47,9 mm (the outer diameter of the piston = 44 mm)
The inner diameter of the new crankcase is approx. 50,5 mm (this crankcase is identified with the improvement code F)
The inner diameter on the old crankcase is approx. 48,5 mm

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