Operation Manual

16
Cleaning the chain saw
Clean the saw regularly with a clean rag. The handles, in
particular, must be kept free of oil.
Checking the plastic housing
Carry out regular visual inspections of all parts of the
housing. If any parts are damaged, have them repaired
immediately and properly in MAKITA authorized service
centers.
Sharpening the saw chain
CAUTION:
• Always withdraw the mains plug and wear safety
gloves when performing work on the saw chain.
Sharpen the saw chain when: (Fig. 35)
– Mealy sawdust is produced when damp wood is cut;
– The chain penetrates the wood with difficulty, even
when heavy pressure is applied;
– The cutting edge is obviously damaged;
– The saw pulls to the left or right in the wood. The
reason for this behavior is uneven sharpening of the
saw chain, or damage to one side only.
Sharpen the saw chain frequently, but remove only a
little material each time.
Two or three strokes with a file are usually sufficient for
routine resharpening. When the saw chain has been
resharpened several times, have it sharpened in MAKITA
authorized service center.
Sharpening criteria:
– All cutter length must be equal. Cutters of differing
length prevent the chain from running smoothly, and
may cause the chain to break.
– Do not sharpen the chain once a minimum cutter length
of 3 mm has been reached. A new chain must then be
fitted.
– The chip thickness is determined by the distance
between the depth gauge (round nose) and the cutting
edge.
– The best cutting results are obtained with following
distance between cutting edge and depth gauge.
Chain blade 91PX: 0.65 mm (Fig. 36)
WARNING:
• An excessive distance increases the risk of kick-back.
– The sharpening angle of 30° must be the same on all
cutters. Differences in angle cause the chain to run
roughly and unevenly, accelerate wear, and lead to
chain breaks.
– The side plate angle of the cutter is determined by the
depth of penetration of the round file. If the specified
file is used properly, the correct side plate angle is
produced automatically.
– Side plate angle for each saw chain are as follows:
Chain blade 91PX: 80° (Fig. 37)
File and file guiding
– Use a special round file (optional accessory) for saw
chains to sharpen the chain. Normal round files are not
suitable.
– Diameter of the round file for each saw chain is as
follows:
Chain blade 91PX: 4.0 mm
– The file should only engage the cutter on the forward
stroke. Lift the file off the cutter on the return stroke.
– Sharpen the shortest cutter first. Then the length of this
shortest cutter becomes the standard for all other
cutters on the saw chain.
– Guide the file as shown in the figure. (Fig. 38)
– The file can be guided more easily if a file holder
(optional accessory) is employed. The file holder has
markings for the correct sharpening angle of 30° (align
the markings parallel to the saw chain) and limits the
depth of penetration (to 4/5 of the file diameter).
(Fig. 39)
– After sharpening the chain, check the height of the
depth gauge using the chain gauge tool (optional
accessory). (Fig. 40)
– Remove any projecting material, however small, with a
special flat file (optional accessory).
– Round off the front of the depth gauge again.
Cleaning the guide bar and lubricating the
return sprocket
CAUTION:
• Always wear safety gloves for this task. Burrs present a
risk of injury.
Check the running surfaces of the bar regularly for
damage. Clean using a suitable tool, and remove burrs if
necessary. (Fig. 41)
If the chain saw receives frequent use, lubricate the return
sprocket bearing at least once a week. Before adding new
fresh grease, carefully clean the 2 mm hole on the tip of
the guide bar, then force a small quantity of multi-purpose
grease (optional accessory) into the hole.
Cleaning the oil guide (Fig. 42)
– Clean the oil guide groove and the oil feed hole in the
bar at regular intervals.
New saw chains
Use two or three saw chains alternately, so that the saw
chain, sprocket and running surfaces of the bar wear
evenly.
Turn the bar over when changing the chain so that the bar
groove wears evenly.
CAUTION:
• Only use chains and bars which are approved for this
model of saw (refer to “SPECIFICATIONS”).
Before fitting a new saw chain, check the condition of the
sprocket. (Fig. 43)
CAUTION:
• A worn sprocket damages a new saw chain. Have the
sprocket replaced in this case.
Always fit a new locking ring when replacing the sprocket.
Maintaining the chain and run-down
brakes
The braking systems are very important safety features.
Like any other component of the chain saw, they are
subject to a certain degree of wear. They must be
inspected regularly by MAKITA authorized service
centers. This measure is for your own safety.