Cleaning The Inside Of The Sprocket Guard; Cleaning The Guide Bar; Replacing The Saw Chain - Makita EA3500S Betriebsanleitung

chain, always switch off the engine and pull the plug cap
off the spark plug (see "Replacing the spark plug"). Always
wear protective gloves!
(Fig. 60)
The chain needs sharpening when:
The sawdust produced when sawing damp wood looks like
wood flour.
The chain penetrates the wood only under great pressure.
The cutting edge is visibly damaged.
The saw is pulled to the left or right when sawing. This is
caused by uneven sharpening of the chain.
Important: Sharpen frequently, but without removing too
much metal!
Generally, 2 or 3 strokes of the file will be enough.
Have the chain resharpened at a service centre when you
have already sharpened it yourself several times.
Proper sharpening
CAUTION: Use only chains and guide bars designed for
this saw!
(Fig. 61)
All cutters must be of the same length (dimension a). Cutters
with different lengths result in rough running of the chain and
can cause cracks in the chain.
The minimum cutter length: 3 mm. Do not resharpen the
chain when the minimum cutter length has been reached; at
this point, the chain must be replaced (see the Extract from
the spare-parts list and "Replacing the saw chain").
The depth of the cut is determined by the difference in height
between the depth limiter (round nose) and the cutting edge.
The best results are obtained with a depth-limiter depth of
0.64 mm (.025").
CAUTION: Excessive depth increases the risk of
kickback! (Fig. 62)
The sharpening angle (α) must be identical for all cutters!
30° for chain type 492 (91PX), 290 (90SG), 291 (90PX)
The teeth will have the proper angle (ß) automatically if the
proper round file is used.
80° for chain type 492 (91PX)
75° for chain type 290 (90SG), 291 (90PX)
Different angles result in a roughly, irregularly running chain,
increase wear and tear and cause chain breakage.
Files and how to work with them
Use a special saw chain round file for sharpening. Standard
round files are unsuitable.
Type 492 (91PX): Saw chain round file, dia. 4.0 mm
Type 290 (90SG), 291 (90PX): Saw chain round file, dia.
The file should cut only when pushed forwards (arrow). Lift
the file when leading it backwards.
First sharpen the shortest cutter. The length of this cutter is
then the standard for all other cutters of the chain.
New saw teeth must be filed to the exact same shape as the
used teeth, including on their running surfaces.
(Fig. 63)
File depending on chain type (90° to the guide bar).
(Fig. 64)
A file holder makes file guidance easier. It is marked for the
correct sharpening angle of:
α = 30°
(keep the marks parallel with the chain when filing, see
illustration) and limits the cut depth to the correct 4/5 of the
file diameter.
(Fig. 65)
After having sharpened the chain, the height of the depth
limiter must be checked by means of a chain gauge.
Correct even the smallest excess height with a special flat
file (1).
Round off the front of the depth limiter (2).
4.5 mm.

7-2. Cleaning the inside of the sprocket guard

(Fig. 66)
CAUTION: Before doing any work on the guide bar or
chain, always switch off the engine and pull the plug cap
off the spark plug (see "Replacing the spark plug"). Always
wear protective gloves!
CAUTION: Start the chain saw only after having
assembled it completely and inspected.
Remove the sprocket guard (1) (see PUTTING INTO
OPERATION for the correct model) and clean out the interior
with a brush.
Remove the chain (2) and guide bar (3).
NOTE:
Make sure there are no residues or foreign matter remaining
in the oil guide groove (4) or on the chain tensioner (5).
To install the guide bar, saw chain, and sprocket guard, see
PUTTING INTO OPERATION for the correct model.
NOTE:
The chain brake is a very important safety device and like
any other component subject to normal wear and tear.
Regular inspection and maintenance are important for
your own safety and must be done by a MAKITA service
centre.
SERVICE
7-3. Cleaning the guide bar (Fig. 67)
CAUTION: Protective gloves must be worn.
Regularly inspect the bearing surfaces of the guide bar (7) for
damage, and clean them with a suitable tool.
Keep the two oiling holes (6) and the entire guide bar clean
and free of foreign matter!
7-4. Replacing the saw chain (Fig. 68)
CAUTION: Use only chains and guide bars designed for
this saw!
Check the sprocket before mounting a new chain.
Worn out sprockets (8) may damage the new chain and must
therefore be replaced.
Remove the sprocket guard (See "PUTTING INTO
OPERATION").
Remove the chain and guide bar.
Remove circlip (9).
CAUTION: The circlip will pop out of the groove. When
removing it, hold your thumb against it to prevent it from
popping off.
Remove shim washer (11).
If the sprocket (8) is worn out, the complete clutch drum (12)
will need to be replaced.
Install a complete new clutch drum (12), shim washer (11)
and new circlip (9).
For replacing the guide bar, chain, and sprocket see
"PUTTING INTO OPERATION".
NOTE:
Don't use a new chain on a worn chain sprocket. By the
time 2 chains have worn, the sprocket has become worn
out, so it should be replaced at least at every second chain
replacement. To distribute the chain oil evenly, run a new
chain at half-throttle for a few minutes before use.
New chains stretch, so check the chain tension frequently
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