RIEJU 125 CBD AC User manual

ENGINE 125 CBD AC
Ei sri maal

Index
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1.INTRODUCTION
1.1 ENQUIRY NOTES 6
1.2 UPDATING GUIDE 6
1.3 WRITING SIMBOLOGY 7
1.4 OPERATIVE SIMBOLOGY 8
1.5 WORK GENERAL RULES 9
1.6 RECOMMENDATIONS 10
1.7 SPARK PLUGS 12
1.8 SPARK PLUG MAINTENANCE 13
1.9 SPARK PLUG REPLACEMENT 13
1.10 MOTOR REMOVAL 13
1.11 MOTOR DISASSEMBLY 13
2.GENERAL SPECIFICATIONS
2.1 TORQUE GENERAL SPECIFICATIONS 14
2.2 LUBRICATION DIAGRAM 15
2.3 VALVES SET ADJUSTMENT 17
2.4 IGNITION POINT CONTROL 21
2.5 COMPRESSION PRESSURE ADJUSTMENT 22
2.6 CHECKING OF THE MOTOR OIL LEVEL 24
2.7 RECOMMENDED MOTOR OIL 24
2.8 MOTOR OIL CHANGE 25
2.9 OIL FLOW CHECKING 26
2.10 EXHAUST SYSTEM CHECKING 27
3.ENGINE
3.1 MOTOR DISASSEMBLY 30
3.2 MAGNETO FLYWHEE 33
3.3 CLUTCH 35
3.4 PUMP OIL 38
3.5 START PEDAL SHAFT 39

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3.6 DISASSEMBLY OF THE START SYSTEM SHAFT WITH PEDAL 40
3.7 CHANGE SHAFT 40
3.8 CHASSIS 41
3.9 ROCKER ARM, TRANSMISSION AND CHANGE SELECTOR 42
3.10 CRANKSHAFT 43
3.11 ROCKERS, CAMSHAFT AND VALVES 44
3.12 CYLINDER HEAD CHECK AND REPAIR 46
3.13 VALVE SEATINGS 48
3.14 VALVES AND VALVE SPRINGS 50
3.15 CAMSHAFT CHECKING 52
3.16 ROCKERS AND THEIR SHAFTS CHECKING 53
3.17 CAMSHAFT CHECKING 54
3.18 TIMING CHAIN STRUT 55
3.19 CYLINDER AND PISTON 55
3.20 RINGS CHECKING 57
3.21 BOLT CHECKING 58
3.22 CRANKSHAFT 59
3.23 ROCKER ARM CHECKING 60
3.24 CLUTCH HOOD CHECKING 61
3.25 CLUTCH CHECKING 61
3.26 ROD OPERATION CHECKING 63
3.27 FORKS AND CHANGE SELECTOR CHECKING 64
3.28 START SYSTEM WITH PEDAL CHECKING 66
3.29 OIL PUMP CHECKING 66
3.30 OIL LEADS CHECKING 67
3.31 CHASSIS 68
3.32 CLAMP RINGS AND WASHERS 68
3.33 MOTOR ASSEMBLY AND ADJUSTMENTS 69
3.34 VALVES AND VALVE SPRINGS CHECKING 70
3.35 ROCKERS AND CAMSHAFT INSTALLATION 72

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3.36 CRANKSHAFT AND ROCKER ARM SHAFT 74
3.37 CHANGE SELECTOR 76
3.38 TRANSMISSION, FORKS AND CHANGE SELECTOR INSTALLATION 77
3.39 TRANSMISSION 78
3.40 CHASSIS 80
3.41 CHASSSIS (RIGHT SIDE) 81
3.42 CHANGE SHAFT AND START SYSTEM WITH PEDAL 83
3.43 CHANGE SELECTOR SEGMENT AND CHANGE SHAFT 84
3.44 START SYSTEM WITH PEDAL INSTALLATION 85
3.45 CLUTCH, HOOD AND OIL PUMP 86
3.46 OIL PUMP INSTALLATION 87
3.47 CLUTCH HOOD INSTALLATION 87
3.48 CLUTCH INSTALLATION 88
3.49 MAGNETO FLYWHEEL 92
3.50 START GEAR CHECKING 93
3.51 MAGNETO ROTOR AND START GEAR 93
3.52 CYLINDER AND PISTON 96
3.53 CONTROL GEAR AND TIMING CHAIN 97
3.54 RINGS, PISTON AND CYLINDERS INSTALLATION 98
3.55 CYLINDER HEAD INSTALLATION 100
3.56 CARBURETTOR 104
3.57 DISASSEMBLY 105
3.58 CHECKING 106
3.59 ASSEMBLY 108
3.60 FUEL LEVEL ADJUSTMENT 110

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Introduction

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Introduction
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1.1 ENQUIRY NOTES
The intervention in control, maintenance, repairs, replacement parts, etc. in the whole range of our
motor vehicle, means not only the competence and experience of the responsible technicians in this
task, in the modern technologies, but also the knowledge of the quick and rational procedures, of
the technical characteristics, of the calibrated values, of the torque, that only manufacturer is in a
condition to lay down for certain.
The present series of WORKSHOP GUIDES for four-stroke engine, provide the main information
for the technicians of the sector (Authorized Dealer, etc...) to operate harmoniously on the modern
concepts of “good technique” and “safety at work”.
The aim of these guides, is about the standard technical interventions in the whole range of engi-
ne (two-stroke engine) for RIEJU motor vehicles in the production phase at the spreading time of
these manuals. This information refers to the “ENGINES” of the motor vehicles. Some information
has been deliberately omitted, since (according to us) it is an essential part of the basic technical
knowledge.
Another possible information, can be deduced from the SPARE PARTS CATALOGUES (of each
particular model).
Before reading the motor vehicle manual you are interested in, it is important that you examine the
first general pages, where you will find the basic information for a good item enquiry and the general
nature technical concepts.
REMARK:
The manual provides you with the essential information for the standard inter-
vention procedures. This information is supplied by the engine manufacturers, so
therefore, this frees us to be responsible for any eventual error, omissions, etc.
The RIEJU company reserves the right to contribute modifications at any time,
without any previous notice.
For any request or further information please call to Rieju Technical Assistance
Service.
1.2 UPDATING GUIDE
•The updating will be send (in a reasonable period). Each new document will replace the one you
have already got.
•The index will be updated in case modifications and changes of the pages inside no longer guaran-
tee a rational enquiry of the manual.
•IMPORTANT! The series of Workshop Guides has to be considered as a work tool, strictly
speaking, and it can remain in “value” through time, only if it is constantly updating.

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1.3 WRITING SIMBOLOGY
ATTENTION ! Some caution advice and information as regards to the safety
of the motorcyclist (vehicle user) and the safeguard of the whole vehicle.
ATTENTION ! Descriptions relating to some dangerous interventions for the
maintenance engineer, the repair technician, the workshop staff or strangers,
for the atmosphere, for the vehicle and for the equipments.
FIRE RISK
Operations which could cause fire.
DANGER OF EXPLOSION
Operations which could cause explosion.
TOXIC
Evident danger of poisoning or inflammation of the first respiratory track.
MECHANICAL MAINTENANCE
Operations to be performed only by an expert mechanic.
ELECTRICAL MAINTENANCE
Operations be performed only by an expert electrical / electronic technician.
NO!
Operations which must be avoided.
ENGINE WOKSHOP GUIDE
Information derived from this documentation.
SPARE PARTS CATALOGUES
Information derived from this documentation.
TOXIC
TOXIC

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Remark:
Illustrations frequently shown fixing or regulator screws, specified with the letter Tr.
The number besides this letter indicates the quantity of identical Tr existing in the
group or object component of the description and its corresponding illustration. The
letter without number, indicates quantity 1. In case of different screws shown in
the same figure, a number and a small letter will follow the letter Tr (example:
(Tr4a).
The re-assembly of groups and components is usually carried out in opposite way
to the disassembly interventions (excepting specified description).
1.4 OPERATIVE SIMBOLOGY
L) Loctite
O) Lubrication (oil)
G) Greasing (grease)
O
L
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F
Pr Tr
P
Ap
S
Es
T
Tr
Figure
Torque
Page
Sub-section
Section
Diagram
Table
Bolt

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1.5 WORK GENERAL RULES
•The following advice, recommendations, and warnings, guarantee rational
interventions in the maximum operative safety, ruling out considerably the probabilities
of accidents, all kind of damage and time-out. Therefore, we advise you to observe them
scrupulously.
ADVICE:
• Always use high quality equipments.
•For raising the motor vehicle, use manufactured equipment on purpose and subject the
European regulations.
•During the operations, tools must be within arm’s reach, as far as possible, according to
a predetermined sequence, and anyway, never on the vehicle or in a hiding or inaccessible
place.
•Keep your workplace duly clean and tidy.
•To tighten bolts and nuts, begin with those of bigger diameter or the interior ones,
proceeding in “cross” in one go and so on.
•The most proper use of the spanner (the fork one), is in one go never pushing.
•The rolling monkey wrench (F-1) have to be used in emergency conditions, this is to say,
when the suitable size tool is not available. During the effort, the mobile clamp tend to open
and this could damage the bolt as well as lead to obtain a torsion moment of an unreliable
tightness. Anyway, use tools like the illustration (figure 1).
•Excluding some exceptional assistance cases, prepare a record card for the Customers,
where all the interventions done and notes for possible controls in future will be entered.
F-1

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1.6 RECOMMENDATIONS
•Before beginning any intervention in the motor vehicle, wait till all and each one of the
components of the same vehicle are completely cool down.
• If the operations need two technicians work, it is necessary that they previously come to
an agreement on tasks and synergies.
• Always check the correct assembly of each component, before assemble another one.
• Lubricate the need spare parts, before re-assembly.
• The linings, the watertight and elastic rings and the pins must be replaced when disassembly
takes place.
• The torque values indicated in the manuals, refer to the “final tight”, and they have to be
progressively reached, in consecutive goes.
• The loosen and tighten operations of the parts in aluminium alloy (sump) must be carried
out when the motor cools down.
• Always use screwdrivers of suitable size for the bolts in use.
•Never work in awkward conditions neither in an unstable situation of the motor
vehicle.
• Never use a lining or an elastic ring again.
•Never unscrew or screw down bolts and nuts with clips since, besides it does not
exert enough blockade force, the bolt cap or the nut hexagon can be damaged.
• Do not hit with the hammer (or another tool) on the spanner to loosen or
tighten bolts and nuts (F-2).
• Do not use the extension bar for the spanner (F-3).
F-2 F-3

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Never use, under no circumstances, free flames.
Never leave open and not suitable containers with fuel, blocking the pass, near to heat
sources, etc.
Never use fuel like a cleansing detergent for the motor vehicle or for the workshop floor.
The components must be cleaned with a low grade of inflammability detergent.
Never suck in or blow in the fuel pipe.
Never carry out welds in the presence of fuel. Remove the tank although it is
totally empty and disconnected the negative (-) lead of the battery.
Never leave the motor running in closed premises or without air vent.
Before each intervention, make sure of the motor vehicle is perfectly steady.
The front wheel should be anchored, preferably, to the integrated tool (A/F-4) in the run-
ning board .
F-4

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1.7 SPARK PLUGS
1. Insulator
2. Body
3. Lining
4. Electrode
5. Earth electrode
6. Thread
SPARK PLUGS CONTROL AT 1.000 Km
• Do not to touch the spark plug if the motor is hot.
• The coal tip and the insulator coloration (around the central electrode) provide with
useful information about the thermic degree of the spark plug, the carburation, the
lubrication and the overall condition of the engine.
• A light brown (insulator) coloration indicates the correct general operation.
• Black sooty tips, dry (to the touch), opaque, indicate that the operation temperature is
too low (spark plug thermic degree is too high), too rich carburation or faulty ignition.
• Off-white insulator indicates: a mixture too weak or spark plug thermic degree too low
(spark plug too hot).
• Verify the distance between the electrodes (F.6) (although the spark plug is new) using
a calibrated calibre of thickness, and eventually, register it working only on the earth
electrode.
F-5
F-6
Pr Tr - Nm
20 - 25

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1.8 SPARK PLUG MAINTENANCE
• The spark plug maintenance consists in removing it periodically from the motor to check
(visually) the conditions and the distance between the electrodes.
• Proceed to clean the electrodes and the insulator carefully, using a wire brush.
• Eliminate possible waste with a strong jet of compressed air.
• Lubricate the thread of the spark plug with motor oil or grease, that conducts electricity,
then screw it by hand until the bottom.
Then press it moderately with the respective spanner (see torque in F.6).
It is necessary to replace all spark plug with fissures in the insulator or corroded
electrodes.
1.9 SPARK PLUG REPLACEMENT AT 5000 Km
• At the foreseen kilometres, replace always the spark plug with a new one, choosing one
of those that the Company RIEJU, S.A. recommends.
• When the discharged spark plug is being eliminated, inspect always its general look (as
previously stated) to check the good state of the engine.
1.10 MOTOR REMOVAL
• To remove the motor from the frame, look up in the Workshop Guide, in “Cyclist”
section, where you will find all the steps to follow.
1.11 MOTOR DISASSEMBLY
The manufacturer is exempt from any responsibility caused by damages of any
nature in a disassembly and a new assembly of the engine and each of its parts,
owing to the use of unsuitable tools for this kind of interventions.
Exclusively use ORIGINAL RIEJU SPARE PARTS.

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General specifications
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2.1 TORQUE GENERAL SPECIFICATIONS
• The following table specifies the fixed torques with ISO standard thread. The torque
specifications for components or special units are indicated in the chapters of this guide
referring to ISO. To avoid strains, screw the units gradually and cross them in one or
alternative goes, to obtain the specified torque..
A= Distances among the planes.
B= External Diameter of the thread.
A (Nut) B (Nut) Torque general specifications
ft.lb
10mm 6mm
19mm 14mm 8,5 61
17mm 12mm 5,5 40
14mm 10mm 3,0 22
12mm 8mm 1,5 11
0,6 4,3
Kgf.mN.m
22mm 16mm
6
85
55
30
15
130 13,0 94

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2.2 LUBRICATION DIAGRAM
Don’t damage the chassis surface, otherwise there will be oil leaks.
Rocker
(Intake)
Rocker
(Exhaust)
Rocker shaft
Oil pump
Centrifugal filter
Camshaft
Oil impeller
Oil in the sump
Drive shaft
Driving shaft
Pull (clutch)
Chassis (LS)

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For a better performance, use always oil and “amalibe”.
Chassis
cowling (RS)
Chassis (RS)
Cylinder head
Cylinder
Centrifugal filter
Chassis (LS)
Chassis
cowling (LS)
Camshaft
Clutch
Driving shaft
Crankshaft
Drive shaft

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2.3 VALVES SET ADJUSTMENT
Remark:
The valves set should be adjust when the motor is cool down and at room tempe-
rature.
When adjusting or measuring the valves set, the piston should be in the top dead
centre (TDC) at the compression moment.
1) REMOVE:
• Spark plug
• Screws (1).
• Lateral cover of the cylinder head (2).
• Valves lining (intake) (3).
• Valves lining (exhaust) (4).
2) REMOVE:
•Top of the point control (with the gasket) (1).
•Central cap (with the gasket) (2)
3) MEASURE:
• Set of valves.
Unspecified => Adjustment
Set of valves (cold):
Intake:
0,08 ~ 0,12 mm
Exhaust:
0, ~ 0,1 mm

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Steps for measuring:
• Rotate the crankshaft anticlockwise aligning the mark (a) of the rotor with the stationary
point (b) of the chassis cover (1), with the piston in the top dead centre (TDC), and when
the mark of the control gear is aligned with the mark of the cylinder head.
• Measure the set of valves with a calibre of thickness.
Unspecified => Set adjustment
4) ADJUST:
• Set of valves.
Steps for measuring:
• Loosen the locknut (1).
• Rotate the adjuster (2) towards the inside or outside with the fixed adjustable spanner (3)
to obtain the specified play.
Turn towards the inside: Play diminishes
Turn towards the outside: Play increases

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• Install the adjuster to impede it turns and tighten the locknut.
Locknut:
, Kgf.m( N.m).
• Measure the set of valves.
• If the play is incorrect, repeat the aforementioned steps until the correct play is
achieved.
5) INSTALL:
• Top of the point control (with the gasket) (1).
• Central cap (with the gasket) (2).
SPARK PLUG CONTROL
1) REMOVE:
• Spark plug connector.
• Spark plug.
Before removing the spark plug, blow on the area with compressed air to
eliminate any piece of dirt, in order to avoid it falls inside the engine.
2) CHECK:
• Spark plug Type.
Incorrect => Replace.
Standard spark plug: 
DR8EA (NGK)

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3) CHECK:
• Electrodes (1).
Damages/Wear => Replacement.
• Insulator (2).
Standard colour => Replacement.
The standard colour is light brown.
4) CLEAN:
• Spark plug.
(Clean the spark plug with a spark plug cleansing or a wire brush).
5) MEASURE:
• Play between the electrodes (a)
(with a calibre of thickness).
Unspecified => Adjustment to play.
Play between the electrodes:
0,7 mm
6) INSTALL:
• Spark plug.
Spark plug:
1, Kgf.m (1 N.m)