Operation Manual

Operating and maintenance information - Maintenance and care of the cutting gear
ENGLISH 34
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Notes on replacing the saw chain and the sprocket
If the saw chain becomes too worn then it will become impossible to re-sharpen it properly and it
should be replaced.
In this case you should also check the condition of the sprocket. A worn sprocket will cause
damage to a brand new saw chain. As a result, you should replace the sprocket together with
the chain.
Always install matching components (sprocket, guide rail, saw chain) (see Chapter 9,
"Permissible cutting gear and further accessories", page 40).
Tip: We recommend the use of two saw chains per sprocket, and that both chains should be replaced
as frequently as possible so that all of the components wear evenly. Once a certain wear limit is
reached, replace all of the parts together again.
644, 651, 651H, 656, 656H 651SP, 656SP
Schematic diagram
of components:
a) Sprocket
b) Washer
c) Retaining ring
d) Bearing
Replacing the sprocket:
• Take off the rail cover, saw chain and guide rail (Chapter 4.1),
• use a screwdriver to take off the retaining ring (c), making sure, with your
gloves on, that it does not jump off.
• Replace the sprocket,
Whenever you replace the sprocket, lubricate the bearing (d) with lithium-
based grease.
• It is best to use flat pliers when refitting the retaining ring.
Please refer to Chapter 4.1, "Installation of the guide rail and saw chain", for more information
on fitting a new saw chain.
Guide bar:
The guide bar of your chainsaw requires just as much care as the saw
chain. The running surfaces must be flat and level, and the groove must
not be widened. Clean the groove and make sure it is free of all foreign
bodies.
In order to prevent one-sided wearing of the guide bar, we recommend
that the guide bar be reversed whenever the chain is sharpened.
On guide bars with a guide sprocket, the bearing of the guide sprocket should
preferably be lubricated with ball bearing grease (through the lubricating hole
on the side with a grease gun) every time the chainsaw is refuelled. Rotate the
guide sprocket while doing this.
Important: The guide bars are only designed to guide the saw chain and must not be used as a
levering tool. Any twisting or turning or use of the guide bar to gain leverage in the wood
shortens the service life of the guide bars.