Stihl 064 User manual

STIHL 064, 066 1
SERVICE MANUAL
064 and 066
Chain Saws
As the design concept of these two models is
almost identical, the descriptions and
servicing procedures generally apply to both.
Differences are described in detail.
You should make use of the illustrated parts
lists while carrying out repair work. They
show the installed positions of the individual
components and assemblies. Microfilmed
parts list are always more up to date than
printed lists.
A fault on the machine may have several
causes. Consult the "troubleshooting charts"
when tracing faults.
Refer to the "Technical Information Bulletins"
for engineering changes which have been
introduced since publication of this service
manual.
Service manuals and technical information
bulletins describing engineering changes are
intended exclusively for the use of STIHL
servicing dealers and staff and must not be
passed on to third parties.
Chain saw on assembly stand
Servicing and repairs are made
considerably easier if the saw is mounted
on assembly stand 5910 850 3100 or 5910
890 3100. This enables the saw to be
swivelled to the best position for the
ongoing repair and thus leaves both hands
free.
The saw is can be quickly secured to the
stand by means of the two bar mounting
studs and nuts.
The STIHL Special Tools manual lists all
special servicing tools currently available
from STIHL.
Always use original STIHL replacement
parts.
Original STIHL parts can be identified by
the STIHl part number, the logo
and the STIHL parts symbol. (
The symbol may appear alone on small
parts.
©
1992
A
n
d
reas
Stihl
.
W
a
ibli
ngen

STIHL 064, 066 2
CONTENTS
1. Specifications 3 4.6 Leakage Testing the 9. Electric Handle
Crankcase 41 Heating System 64
1.1 Engine 3 4.6.1 Preparations 41
1.2 Fuel System 4 4.6.2 Pressure Test 42 9.1 Troubleshooting 64
1.3 Ignition System 5 4.6.3 Vacuum Test 43 9.1.1 Troubleshooting Chart 65
1.4 Cutting Attachment 5 4.7 Replacing the Oil Seals 44 9.1.2 Test Connections and
1.5 Tightening Torques 7 Test Values 66
1.6 Special Accessories 8 9.2 Switch 67
1.6.1 For User 8 5. Ignition System 45 9.3 Heating Element in Rear
1.6.2 For Service 8 Handle 67
5.1 Repairing Component 9.4 Heating Element in
Parts 46 Front Handle 68
2. Troubleshooting 5.1.1 Spark Plug 46 9.5 Generator 69
Charts 9 5.1.2 Ignition Lead/Spark
Plug Terminal 48
2.1 Clutch, Chain Drive 5.1.3 Short Circuit Wire/ 10. Chain Lubrication 72
Chain Brake and Ground Wire 49
Chain Tensioner 9 5.1.4 Stop Contact 51 10.1 Pickup Body 72
2.2 Engine 10 5.1.5 Flywheel 52 10.2 Suction Hose 73
2.3 Ignition System 11 5.1.6 Ignition Module 53 10.3 Vent Valve 73
2.4 Rewind Starter 12 5.1.6.1 Ignition Timing 54 10.4 Removal and Installation
2.5 Chain Lubrication 13 5.1.6.2 Removing and of Oil Pump 73
2.6 Fuel System 14 Installing 54 10.5 Servicing the Oil Pump 75
5.1.7 LED (066 only) 55
3. Clutch, Chain Drive 11. Fuel System 76
Chain Brake and Chain 6. Rewind Starter 56
Tensioner 16 11.1 Air Filter 76
6.1 Routine Maintenance 56 11.2 Construction and
3.1 Clutch Drum/Chain 6.2 Rope Rotor/Pawls 56 Operation of Carburetor
Sprocket 16 6.3 Replacing the Starter with Compensator 77
3.2 Clutch 17 Rope 57 11.3 Leakage Testing the
3.3 Chain Brake 19 6.4 Replacing the Rewind Carburetor 78
3.3.1 Disassembly 19 Spring 57 11.4 Removal and Installation
3.3.2 Assembly 21 6.5 Tensioning Rewind of Carburetor 79
3.4 Chain Tensioner 23 Spring 58 11.5 Servicing the
3.5 Bar mounting studs 24 6.6 Replacing Starter Rope Carburetor 80
Guide Bush 59 11.6 Carburetor Adjustment
(Analog Ignition) 85
4. Engine 25 11.7 Carburetor Adjustment
7. AV Handle System 60 (Digital Ignition) 86
4.1 Removing and Refitting 11.8 Tank Vent 87
Exhaust Muffler 25 7.1 Repair 60 11.9 Fuel Filter and
4.2 Exposing the Cylinder 26 Fuel Hose 88
4.3 Cylinder and Piston 26 11.10 Tank Housing 89
4.3.1 Removal 26 8. Master Control 61 11.11 Carburetor Box 91
4.3.2 Installation 27
4.4 Piston Rings 31 8.1 Construction and
4.5 Crankcase 32 Function 61 12. Special Servicing
4.5.1 Removing the 8.2 Throttle Trigger/Inter- Tools and Aids 92
Crankshaft 32 lock Lever 62
4.5.2 Installing the 8.2 Switch Shaft 63 12.1 Special Servicing Tools 92
Crankshaft 35 12.2 Servicing Aids 93

STIHL 064, 066 3
1. SPECIFICATIONS
1.1 Engine 064 066
STIHL single-cylinder two-stroke
engine
Displacement: 85 cm³ (5.2 cu.in) 91.6 cm³ (5.6 cu.in)
Bore: 52 mm (2.05 in) 54 mm (2.12 in)
Stroke: 40 mm (1.6 in) 40 mm (1.6 in)
Compression ratio: 10.0 10.0
Power output: 4.8 kW (6.5 bhp) 5.0 kW (6.8 bhp)
at 9,500 rpm at 9,500 rpm
Max. torque: 5.45 Nm (4.0 Ib.ft) 5.6 Nm (4.1 Ib.ft)
at 6,500 rpm at 6,500 rpm
Cylinder bore: Highly wear-resistant electroplated coating
Max. permissible engine
speed with bar and
chain: 12,000 rpm
Cut-off speed: 13,500 rpm
Mean idle speed: 2,400 rpm 2,400 rpm
Crankshaft: Two-part, drop forged Two-part, drop forged
Crankshaft bearings: 2 deep groove ball bearings 2 deep groove ball bearings
Crankpin diameter: 16 mm (0.63 in) 16 mm (0.63 in)
Big-end bearing: Needle cage Needle cage
Piston pin dia.: 12 mm (0.47 in) 12 mm (0.47 in)
Small-end bearing: Needle cage Needle cage
Conrod length: 68 mm (2.67 in) 68 mm (2.67 in)
Rewind starter: Two-pawl system with automatic starter rope
rewind mechanism
Starter rope: 4.5 mm (0.18 in) dia., length 1000 mm (39.4 in)
Clutch: Centrifugal clutch Centrifugal clutch
without linings, without linings,
82 mm (3.2 in) dia. 82 mm (3.2 in) dia.
Clutch engages at: approx. 3,200 rpm approx. 3,200 rpm
Crankcase leakage test
at gauge pressure: 0.5 bar (7.25 psi) 0.5 bar (7.25 psi)
under vacuum: 0.5 bar (7.25 psi) 0.5 bar (7.25 psi)

STIHL 064, 066 4
1.2 Fuel System 064 066
Carburetor: All position diaphragm All position diaphragm
carburetor with integral carburetor with integral
fuel pump fuel pump
Basic setting
High speed screw H: Back off approx. 1 turn Back off approx. 1 turn
Low speed screw L: Back off approx. 1 turn Back off approx. 1 turn
(starting with screws (starting with screws
tight against their tight against their
seats) seats)
Carburetor leakage test
at gauge pressure: 0.4 bar (5.8 psi) 0.4 bar (5.8 psi)
Fuel tank capacity: 0.84 I (1.77 US pt) 0.84 I (1.77 US pt)
Fuel mixture: Regular brand-name gasoline and brand-name two-stroke
engine oil
Mix ratio: 50:1 50:1
with STIHL two-stroke engine oil with STIHL two-stroke engine oil
25:1 25:1
with other brand-name two-stroke, with other brand-name two-stroke,
air-cooled engine oils air-cooled engine oils
Compensator: Keeps pressures equal at clean
air side of filter and metering
diaphragm irrespective of how dirty
the filter is
Air filter: Standard (wire mesh) Standard (wire mesh)
element element
Special accessory: Special accessory:
Heavy duty (HD)-air filter Heavy duty (HD)-air filter

STIHL 064, 066 5
1.3 Ignition System 064 066
Type: Electronic magneto Digital magneto
ignition (breakerless) ignition (breakerless)
with integral trigger with maximum speed
unit governor
Air gap: 0.2-0.3 mm (0.008-0.012 in) 0.2-0.3 mm (0.008-0.012 in)
Ignition timing: 2.6-3.4 mm 2.9-3.9 mm
(0.10-0.13 in) B.T.D.C. (0.11-0.15 in) B.T.D.C.
at 8,000 rpm at 8,000 rpm
Advance angle: 26°-30° B.T.D.C. 27.5°-32.5° B.T.D.C.
at 8,000 rpm at 8,000 rpm
Spark plug (suppressed): Bosch WSR 6 F or Bosch WSR 6 F or
NGK BPMR 7 A NGK BPMR 7 A
Electrode gap: 0.5 mm (0.020 in) 0.5 mm (0.020 in)
Spark plug thread: M14 x 1.25 M14 x 1.25
Length of thread: 9.5 mm (0.37 in) 9.5 mm (0,37 in)
Heat range: 200 200
LED: Aids carburetor adjustment
1.4 Cutting Attachment
Guide bars: STIHL Rollomatic S bars STIHL Rollomatic S bars
with sprocket nose. with sprocket nose.
STIHL Duromatic bars STIHL Duromatic bars
with stellite-tipped with stellite-tipped
nose. nose.
Both types with Both types with
corrosion-resistant corrosion-resistant
finish and induction finish and induction
hardened rails. hardened rails.
Bar lengths: Rollomatic: 40, 45, 50 Rollomatic: 40, 45, 50
63, 75 and 90 cm 63, 75 and 90 cm
(16, 18, 20, 25, 30 (16, 18, 20, 25, 30
and 35 in) and 35 in)
Duromatic: 40, 45, 50, Duromatic: 40, 45, 50,
63 and 75 cm 63 and 75 cm
(16, 18, 20, 25 and 30 in) (16, 18, 20, 25 and 30 in)

STIHL 064, 066 6
064 066
Oilomatic chain: 3/8" (9.32 mm) 3/8" (9.32 mm)
Rapid Micro and Super Rapid Micro and Super
(standard) (standard)
0.404" (10.26 mm) 0.404" (10.26 mm)
Rapid Micro and Rapid Super Rapid Micro and Rapid Super
(optional) (optional)
Chain sprocket: 8-tooth 3/8" rim or 8-tooth 3/8" rim or
spur sprocket spur sprocket
(alternatives) (alternatives)
7-tooth 0.404" spur 7-tooth 0.404" spur
or rim sprocket or rim sprocket
(optional) (optional)
Chain speed: 23.6 m/s (77.4 ft/s) 23.6 m/s (77.4 ft/s)
at 9,500 rpm at 9,500 rpm
(with 8-tooth 3/8" (with 8-tooth 3/8"
chain sprocket) chain sprocket)
Chain lubrication: Fully automatic, speed- Fully automatic, speed-
controlled reciprocating controlled reciprocating
oil pump, no feed at oil pump, no feed at
idle speed. Additional idle speed. Additional
manual oil flow control. manual oil flow control.
Oil feed rate,
adjustable: 11-21.5 cc/min 11-21.5 cc/min
(3/8-3/4 fl.oz/min) (3/8-3/4 fl.oz/min)
at 10,000 rpm at 10,000 rpm
Oil tank capacity: 0.35 l (0.74 US pt) 0.35 l (0.74 US pt)

STIHL 064, 066 7
1.5 Tightening Torques
Fastener Thread size For component Torque Remarks
Nm (Ibf.ft)
Spline screw IS-M5x20 Crankcase 9.0 (6.6)
Spline screw IS-M5x20 Cylinder 12.0 (8.8)
Spline screw IS-M6x20 Cylinder 15.0 (11.8) 4)
Spline screw IS-M5x12 Muffler to cylinder 10.0 (7.5) 1)2)
Spline screw IS-M6x20 Muffler to cylinder 15.0 (11.0) 4)
Spline screw IS-M5x6 Muffler upper casing (top) 11.0 (8.1) 1)2)
Spline screw IS-M5x12 Muffler upper casing (bottom) 8.0 (5.9) 1)2)
Spline screw IS-M5x20 Ignition module 9.0 (6.6) 1)2)
Nut M8x1 Crankshaft (flywheel) 33.0 (24.3)
Flange locknut VM 5 Carburetor 3.5 (2.6)
Spline screw IS-M4x16 Shroud 3.0 (2.2) 1)2)
M12x1 L Clutch carrier 50.0 (37.0)
M14x1.25 Spark plug 25.0 (18.5)
Spline screw IS-6x19 Annular buffer (top) 3.5 (2.6)
Spline screw IS-6x19 Annular buffer (bottom) 7.0 (5.2)
Spline screw IS-5.8x19 Front handle 7.0 (5.2) 2)3)
Self-tapping screw B3.9x19 Handle molding 1.0 (0.75)
Spline screw IS-M5x12 Annular buffer plate 9.0 (6.6) 1)
Spline screw IS-M5x16 Chain catcher 7.0 (5.2)
Spline screw IS-M5x12 Spiked bumper (top) 7.0 (5.2)
Spline screw IS-M5x16 Chain catcher pin
to spiked bumper 6.0 (4.4)
Spline screw IS-M5x12 Rubber buffer to crankcase 3.5 (2.6)
Locknut M5 Spiked bumper to sprocket cover 8.0 (5.9)
Pan head screw BM3x8 Guard in sprocket cover 1.0 (0.75)
Pan head screw M3.5x12 Generator (heating) 2.0 (1.5)
Pan head screw M4x12 Cover (chain tensioner) 3.5 (2.6)
Spline screw IS-M4x12 Oil pump 3.0 (2.2)
Spline screw IS-M4x12 Cover (chain brake) 2.0 (1.5)
Spline screw IS-M5x18 Fan housing 3.5 (2.6)
Spline screw IS-M5x12 Starter post in fan housing 6.0 (4.4)
Starter post M8 Fan housing 6.0 (4.4)
Screw assy. IS-M5x30 Hand guard (left) 7.0 (5.2) 1)
Pan head screw M4x8 Inner side plate 3.0 (2.2)
Collar stud M8 Guide bar mounting 15.0 (11.0) 1)
Remarks:
1) Screw must be secured with adhesive 0786 111 1101 (Loctite 242).
2) Washer must be fitted under screw head. On front handle, fit washer under heads of side screws only.
3) Screw must be secured with adhesive 0786 111 1117 (Loctite 648).
4) Model 066 only.
Note: Screws secured with adhesive are easier to release if the adhesive is heated first with a hot air blower
(hair dryer). Exercise caution on polymer components.

STIHL 064, 066 8
1.6 Special Accessories 064 / 066
1.6.1 For User
STIHL repair kit 064 1122 900 5000
Intake air preheating kit 1122 007 1027
7-tooth 0.404" rim
sprocket kit 1122 007 1002
8-tooth 3/8" spur
sprocket 1122 640 2000
7-tooth 0.404" spur
sprocket 1122 640 2001
Valve (fuel tank vent) 1110 353 1600
0.404" (10.26 mm) Oilomatic
chains
Spiked bumpers for thick bark
1.6.2 For Service
Carburetor parts kit 064 1122 007 1060
Gasket set 064/066 1122 007 1051

STIHL 064, 066 9
2. TROUBLESHOOTING
CHARTS
2.1 Clutch,
Chain Drive,
Chain Brake and
Chain Tensioner
Condition
Saw chain turns at
idle speed
Cause
Engine idle speed too high
Spring hook(s) broken
Remedy
Readjust at idle speed
adjustment screw
(counterclockwise)
Fit new spring(s)
Loud noises Springs stretched or fatigued
Needle cage damaged
Clutch shoe retainer
broken
Clutch shoes and carrier
worn
Replace all clutch springs
Fit new needle cage
Fit new retainer
Fit new clutch
Chain sprocket wears
rapidly
Chain wears rapidly
Chain not properly
tensioned
Chain not properly
tensioned
Poor chain lubrication
rectify problem
Worn chain sprocket
Tension chain as specified
Tension chain as specified
Check chain lubrication and
Fit new sprocket
Chain does not stop
immediately when chain brake
is activated
Brake spring broken
Brake band stretched or
broken
Fit new brake spring
Fit new brake band

STIHL 064, 066 10
Always check and, if necessary, repair the following parts before looking for faults on the engine:
- Air filter
- Fuel system
- Carburetor
- Ignition system
Condition Cause Remedy
Engine does not start Oil seals in crankcase Replace oil seals
easily, stalls at leaking
idle speed, but
operates normally Manifold leaking Seal or replace manifold
at full throttle
Cylinder base gasket Replace gasket
leaking
Crankcase damaged (cracks) Replace crankcase
Engine does not Secondary air seepage Mount manifold correctly or
deliver full power through poorly mounted replace
or runs erratically or faulty manifold
Piston rings leaking Fit new piston rings
or broken
Muffler carbonized Clean muffler (inlet and
exhaust), replace spark
arrestor screen (if fitted)
Engine overheating Insufficient cylinder Thoroughly clean all cooling
cooling. Air inlets in air openings
fan housing blocked or
cooling fins on cylinder
very dirty
Intake air preheating Remove intake air preheating
being used at too high components; close rotary
an outside temperature shutter
2.2 Engine