21-63G-00
PB-655, PB-755
1
2
INTRODUCTION
We are constantly working on technical
improvement of our products. For this reason,
technical data, equipment and design are
subject to change without notice. All
specifications and directions in this SERVICE
DATA are based on the latest products
information available at the time of
publication. ECHO SERVICE MANUAL Ord.
No. 403-12 contains lots of information for
servicing these models.
CONTENTS
page
1 SERVICE INFORMATION ............................. 2
1-1 Specification ............................................... 2
1-2 Technical data ............................................ 3
1-3 Torque limits ............................................... 3
1-4 Special repairing materials......................... 4
1-5 Service limits .............................................. 5
1-6 Special tools ............................................... 6
2 CARBURETTOR ADJUSTMENT PROCEDURE .
2-1 General adjusting rules .............................. 7
2-2 Idle adjust screw, idle mixture needle and hi
speed (H) mixture needle initial settings........... 7
2-3 Adjusting carburettor .................................. 8
Reference No. 21-63G-00
ISSUED: 200705
7
INDEX
PB-655
2
1 SERVICE INFORMATION
1-1 Specifications
Model PB-655 PB-755
Dimensions Length* mm(in) 380 (15.0)
Width* mm(in) 480 (18.9)
Height* mm(in) 525 (20.7)
Dry weight** kg(lb) 11.3 (24.89) 11.9 (26.21)
Engine Type KIORITZ, air-cooled, two-stroke, single cylinder
Rotation Anticlockwise as viewed from the output end
Displacement cm3(in3) 63.3 (3.86)
Bore mm(in) 48.0 (1.89)
Stroke mm(in) 35.0 (1.38)
Compression ratio 6.3
Carburettor Type Diaphragm, horizontal-draught, with primer
Model Walbro WYK-192
Ignition Type CDI (Capacitor discharge ignition) system
Spark plug BPM8Y
Exhaust Muffler type Spark arrestor muffler
Starter Type Automatic rewind
Rope diameter x length mm(in) 3.5 x 1000 (9/64 x 39 1/2)
Fuel Type Premixed two-stroke fuel
Mixture ratio 50 : 1 (2 %)
Petrol Minimum 89 octane unleaded
Two-stroke air cooled engine oil ISO-L-EGD (ISO/CD13738), JASO FC/FD
Tank capacity L (U.S.fl.oz.) 2.0 (67.7)
Throttle Mount Tube-mounted throttle with cruise control
Blower Fan type Centrifugal, single stage
Max. air volume (with pipes)
m3/min (ft3/min) 17.7 (625)**
Max. air velocity (with pipes)
Discharge ID mm (in) 70 (2.75)
ID : Inner diameter.
* Without flexible pipe and blower pipes.
SERVICE INFORMATION
m/s (mph) 92 (205)
PB-755
** With frexible pipe and blower pipes.
PB-655
PB-755
1-2 Technical data
Model PB-655 PB-755
Engine
Idling speed r/min 2400 - 2800
Wide open throttle speed r/min 6800 - 7300
Compression pressure MPa (kgf/cm2) (psi) 1.05 (10.7) (152)
Ignition system
Spark plug gap mm(in) 0.6 - 0.7 (0.024 - 0.028)
Minimum secondary voltage at 1000 r/min kV 12
Primary coil resistance Ω 150 - 250
Secondary coil resistance kΩ 1.2 - 1.8
Pole shoe air gaps mm(in) 0.3 - 0.4 (0.012 - 0.016)
Ignition timing °BTDC 30
Carburettor
Venturi size mm(in) 15.0 (0.591)
Throttle bore mm(in) 15.0 (0.591)
Idle adjust screw initial setting turn back* 8
Idle mixture needle initial setting turn in** 10
H mixture needle initial setting turn back 3 3/4
Test Pressure, minimum MPa (kgf/cm2) (psi) 0.05 (0.5) (7.0)
Metering lever height mm(in) 1.5 (0.06) lower than diaphragm seat
SERVICE INFORMATION
3
BTDC: Before top dead centre.
* Refer to page 7 on 2-2 initial idle adjust screw.
** Screw in idle mixture needle from initial thread engagement (at the point that the clicking sound is heard).
4
1-3 Torque limits
Descriptions Size kgf•cm N•m in•lbf
Starter Starter pawl assembly M 10 80 - 100 8 - 10 70 - 90
system Starter case M 5*** 35 - 50 3.5 - 5 30 - 45
Ignition Flywheel M 10 200 - 240 20 - 24 175 - 210
system C.D.I module M 5 60 - 100 6 - 10 50 - 90
Fuel Spark plug M 14 150 - 170 15 - 17 130 - 150
system Carburettor M 5 40 - 55 4 - 5.5 35 - 48
Intake insulator M 5 35 - 45 3.5 - 4.5 30 - 40
Fuel tank M 5 20 - 40 2 - 4 17 - 35
Engine Crankcase M 5 70 - 110 7 - 11 60 - 95
Cylinder M 5 70 - 110 7 - 11 60 - 95
Engine plate M 5* 20 - 40 2 - 4 17 - 35
Engine mount M 6 100 - 150 10 - 15 90 - 130
Cylinder cover M 5 40 - 55 4 - 5.5 35 - 48
Engine cover M 5** 20 - 40 2 - 4 17 - 35
Muffler M 6*** 110 - 150 11 - 15 95 - 130
Muffler stay M 5 70 - 110 7 - 11 60 - 95
Exhaust guide M 4 15 - 25 1.5 - 2.5 13 - 22
Others Fan M 5 50 - 75 5 - 7.5 45 - 65
Fan case M 5** 40 - 55 4 - 5.5 35 - 48
Blower grid M 5** 20 - 40 2 - 4 17 - 35
Cushion
Frame side M 5*** 20 - 40 2 - 4 17 - 35
Fan case side
Main pipe M 5 20 - 40 2 - 4 17 - 35
High tension lead clip M 5** 40 - 50 4 - 5 35 - 45
Harness fixture M 5** 20 - 40 2 - 4 17 - 35
Throttle lever
Regular bolt, nut and screw M 3 6 - 10 0.6 - 1 5 - 9
Top M 5** 20 - 40 2 - 4 17 - 35
Bottoms M 5** 80 - 100 8 - 10 70 - 90
††
SERVICE INFORMATION
M 6 20 - 30 2 - 3 17 - 26
M 4 15 - 25 1.5 - 2.5 13 - 22
M 5 25 - 45 2.5 - 4.5 22 - 40
M 6 45 - 75 4.5 - 7.5 40 - 65
M 8 110 - 150 11 - 15 95 - 130
PB-655
PB-755
* Tapping screw
** Tapping bolt
*** Apply thread locking sealant (See below)
1-4 Special repairing materials
Material Location Remarks
Grease Rewind spring
Starter center post Lithium based grease
Oil seal inner lips
Thread locking sealant Ball bearing Loctite #675 or equivalent
Muffler Loctite #242, ThreeBond #1324 or equivalent
Starter case Loctite #222, ThreeBond #1342 or equivalent
Cushion (Frame side) Loctite #222, ThreeBond #1342 or equivalent
PB-655
PB-755
1-5 Service limits
ABCD
SERVICE INFORMATION
5
5K247
5K248
5K249 5K250
EFGH
5K251 5K016 5K042
5K252
KL
5K219 5K220
Description mm(in)
A Cylinder bore When plating is worn and aluminum can be seen
B Piston outer diameter Min. 47. 95 (1.888)
C Piston pin bore Max. 10.030 (0.395)
D Piston ring groove, 1st Max. 1. 65 (0.065)
2nd Max. 1. 6 (0.063)
E Piston ring side clearance Max. 0. 1 (0.004)
F Piston pin outer diameter Min. 9. 98 (0.393)
G Piston ring width Min. 1. 45 (0.057)
H Piston ring end gap Max. 0. 5 (0.02)
K Con-rod small end bore Max. 14. 025 (0.552)
L Crankshaft runout Max. 0.05 (0.002)
6
2
0
4
0
6
0
8
0
1
2
0
1
4
0
1
6
0
1
8
0
2
0
1
0
0
1-6 Special tools
1
2
#.014 = .35mm
Ignition Air Gap Gauge
P/N 91004
SERVICE INFORMATION
3: a
= 4 mm
4: a = 5 mm
a
5
PB-655
PB-755
6
7
8: a = 8 mm
10 11 12
9: a = 10 mm
1.3
1.65
0.4
1.5
a
1413 16 17
1918 20
15
21
6
8
0
0
4
0
1
2
0
0
0
22
1
2
0
1
4
0
1
6
0
1
8
0
2
0
ECHO
Key Part Number Description Used for:
1 897801-33330 Tachometer PET-1000 Measuring engine speed to adjust carburettor
2 91004 Module air gap gauge Adjusting pole shoe air gaps
3 895610-79920 L-hex wrench (4 mm) Socket bolt (M5)
4 895611-79920 L-hex wrench (5 mm) Socket bolt (M6)
5 897501-03938 Puller Removing magnetor rotor
6 897537-30130 Piston stopper Locking crankshaft rotation
7 897563-19830 Metering lever gauge Measuring metering lever height on carburettor
8 897558-02830 T-socket wrench(8mm) Removing and installing hex.bolt (M5)
9 897558-10230
T-socket wrench(10mm)
Removing and installing hex.bolt (M6)
10 897701-14732 Bearing tool Removing and installing crankcase ball bearings
11 897702-30131 Piston pin tool Removing and installing piston pin (Use 10 mm dia. adapter.)
12 897712-07930 2-pin wrench Removing and installing pawl carrier
13 897719-02830 Piston holder Making piston steady to remove and install piston/rings
14 897726-21430 Oil seal tool Installing crankcase oil seal
15 897800-79931 Spark tester Checking ignition system
16 897803-30131 Pressure tester Testing carburettor and crankcase leakage
17 897826-16131 Rubber plug Testing crankcase and cylinder leakage
18 897827-16131 Pressure plate Testing crankcase and cylinder leakage
19 897834-79930 Rubber plug Testing crankcase and cylinder leakage
20 897835-16131 Pressure connector Testing crankcase and cylinder leakage
21 91007 Compression gauge Measuring cylinder compression
2 2 91020 Limiter plug tool Removing and installing plug
PB-655
PB-755
2 CARBURETTOR ADJUSTMENT PROCEDURE
2-1 General adjusting rules
A. Before starting the unit for adjustment, check the following items.
1. The correct spark plug must be clean and properly gapped.
2. The air filter element must be clean and properly installed.
3. The muffler exhaust port must be clear of carbon.
4. The fuel lines, tank vent and fuel filter are in good condition and clear of debris.
5. The fuel is fresh ( > 89 octane : RON ) and properly mixed at 50 : 1 with “ISO L-EGD” or “JASO FC/FD”
2 stroke oil.
6. All blower pipes are installed for proper engine loading.
B. Start and run engine for 3 minutes alternating rpm between WOT for 50 seconds and idle for 10 seconds.
Adjust idle speed screw to 2,600 +/- 200 r/min. If engine does not run correctly after this adjustment,
proceed to the next step 2-2.
IMPORTANT : After adjusting carburettor according to the steps 2-2 and 2-3, the limiter plug(s)
must be installed in Idle and hi speed (H) mixture needle(s) hole(s) to comply with Emission Directive.
SERVICE INFORMATION
7
2-2 Initial idle adjust screw, idle mixture needle and hi speed (H) mixture needle settings
1. Remove plugs from Idle mixture needle hole (A)
and H mixture needle hole (B) using limiter plug
tool (C) as follows.
(1)Put limiter plug tool (C) on limiter plug in mixture
needle hole.
(2)Push and turn limiter plug tool anticlockwise 2
turns into limiter plug slowly.
(3)Pull out limiter plug tool with the limiter plug from
mixture needle hole.
(4)Repeat plug removal procedure for the other
mixture needle.
NOTE : When plug is damaged and left in the hole,
use needle or pin-shaped tool to scrape.
2. Turn hi speed (H) mixture needle (B) clockwise
until lightly seated. And then turn hi speed (H)
mixture needle anticlockwise 3 3/4 turns.
Turn idle mixture needle (A) anticlockwise
completely out until a clicking sound is heard. Then
turn it clockwise 10 turns from the point that the
clicking sound is heard.
3. Turn idle adjust screw (D) clockwise until its head
touches boss (G) as shown Fig 1. Then turn idle
adjust screw (D) anticlockwise 8 turns from the point
as shown Fig 2.
(C)
(A)
(D)
(B)
(1)
(G)
(2)
Fig1
(3)
Fig2
NOTE : Initial carburettor setting (Idle adjust screw, idle and hi speed (H) mixture needles) shown here is
to start the engine after restoration or carburettor change. Idle adjust screw, idle and H mixture needles
turn for designated engine revolution through procedures indicated here may vary. As long as idle and
WOT engine speed is set in given range, the variance would be ignorable.
8
2-3 Adjusting carburettor
SERVICE INFORMATION
PB-655
PB-755
(E)
1. Start engine and warm it up alternating engine
speed between WOT and idle every 10 seconds for
1 minute.
2. Adjust idle mixture needle with 2.5 mm blade
screwdriver (E) to reach maximum engine speed
just before drop off.
3. Set idle speed to 2,800 r/min by turning idle adjust
screw. Engine speed ranges 2,800 +/- 30 r/min after
idle adjust screw adjustment.
4. Turn idle mixture needle anticlockwise to reduce
idle speed 200 to 300 r/min in the range of 2,500 to
2,600 r/min.
NOTE : Engine speed must be allowed to stabilize
a minimum of 20 seconds after each adjustment of
L mixture needle to assure accurate tachometer
readings.
5. Adjust hi speed (H) mixture needle and obtain
maximum WOT engine speed just before lean drop
off using 2.5mm blade screwdriver.
(F)
(C)
6. Turn hi speed (H) mixture needle anticlockwise
to reduce WOT engine speed 10-20 r/min. Minimum
WOT engine speed after adjusting should be over
6,800 r/min.
7. Start engine, and verify engine idle speed ranges
from 2,400 to 2,800 r/min, and WOT engine speed
ranges from 6,800 to 7,300 r/min. When final
adjustment is completed, the engine should idle,
accelerate smoothly, and attain WOT per above
specification.
8. After adjusting carburettor, insert and secure new
plug(s) (F) A259-000000 deep in the needle holes
per the Emission Directive using limiter plug tool (C).
NOTE : Engine WOT, and idle speed r/min in field
operation may vary from final adjustment
specifications due to changing ambient conditions,
fuel, and engine loads. Safe engine rpm variances
should be within the WOT, Idle speed ranges listed
in Section 1-1, otherwise the carburetor should be
readjusted.
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