MZ 125 SX Operating instructions

RepairManual
MZ 125 SXJSM
Reproduced for
---"l-
MOTORRAO- UNO ZWEIRAOWERK GMBH
8080116ENG

-~
Foreword
This repair manual explains the mostimportantwork proceduresfor the main components of the MZ
125 SXlSM. Itis primarily oriented toward MZ service stations with qualified, trained personnel and
individuals with atechnical understanding
of the mechanical concepts and processes. All indications
and descriptions refer to amotorcycle as delivered by the factory. Work on accessories and their
mounting are not covered here. Repairs and maintenance work should only be performed with
sufficient knowledge and experience and not based on this manual alone.
We are not liable for damages due to:
unauthorized technical modifications
installation
of parts which are not original replacement parts or accessories
installation of accessories not intended for the specific model
improper repair work on MZ vehicles!
This repair manual contains various hazard warnings, important information and tips.
Please pay careful attention to this information to eliminate the risk
of injury during maintenance and
repair work. Incorrect maintenance
or repairs can endanger life and health or damage the vehicle.
Pleasealso notethat the hazard warnings, importantinformation and tips are notexhaustive. Itwould
be impossibleto warn against all possible hazards and consequenceswhich could result from failure
to follow these instructions.
We are constantly working on the further development of our vehicles. For this reason, we reserve
the
rightto makechanges in the interests oftechnical progress (equipment, shape, technology, etc.).
This repair manual is based on the most recent information available atthe time
of publishing. There-
fore, no claims may be derived from the information, figures and descriptions
in this repair manual.
The illustrations also do not necessarily perfectly depict the vehicle to
be repaired.
This repair manual is protected by copyright. Reprinting, reproduction or
translation, even
of excerpts, is not permitted without approval by MZ. MZ Motorrad- und Zweirad-
werk GmbH expressly retains all rights granted under copyright law.
©2002 Motorrad- und Zweiradwerk GmbH
PF 1170,
Alte Marienberger Straf),e 30 -35
D-09401 Zschopau-Hohndorf, Germany
Technical Customer Service
Telephone: [phone]
Fax: [phone]
e-mail: [email protected]
Internet: http://www.muz.de
MZ 125 SXlSM RepairManual 05/02

05/02
MZ 125SXlSM Repair Manual

1
1.1
1.2
1.3
1.4
15
2
2.1
2.2
2.3
2.4
2.5
2.5.1
2.5.2
3
3.1
3.2
3.3
3.4
3.4.1
3.4.2
3.4.3
3.5
3.5.1
3.5.2
3.5.3
3.5.4
3.5.5
3.5.6
3.6
3.6.1
3.6.2
3.6.3
3.6.4
3.7
3.8
3.9
3.9.1
3.9.2
3.9.3
3.10
3.10.1
3.10.2
3.10.3
3.10.4
3.10.5
3.10.6
3.10.7
3.10.8
3.10.9
3.10.10
3.10.11
Table of Contents
Table of Contents
Safety Regulations and Information 5
Important Information .. 5
Safety Regulations 6
Important Work Information..
.. 6
Important Maintenance Instructions . 6
Identification .... 7
Data Sheets 9
Technical Data 9
Inspection .. 13
Lubrication Points 15
Special Tools..... .. 16
Tightening torques.......... . 18
Chassis 18
Engine .20
Chassis 23
Seat .. 23
Locking Hoop
.... 24
Side Panelling .. 24
Fuel Tank .. 25
Filter Valve
.. 26
Tank Cap..............
.. 27
Fuel Filter 27
Lighting/Signal System.
.. 28
Headlight
.. 28
Tum Indicator Lights.....................................
.. 30
Headlight Casing
31
Adjusting the Headlight... .. 32
Tail Ligh!..........................
.. 32
Ignition Steering Lock.................
.. 33
Instruments........... .34
Speedometer and Lighting
34
Indication Lights .. 34
Reset Button.......... .. 35
Instrument Mount.... .. 35
Ignition Lock 36
Front Wheel Mud Guard 37
Rear Wheel Mud Guard 38
Rear Wheel Mud Guard
.. 38
Rear Reflector 38
Shock Absorber Protector 38
Handlebar 39
Mirror 39
Bowden cables
39
Throttle Twist Grip 40
Rubber Grips 40
Handlebar
41
Swingarm 42
Hand Brake Lever 42
Front Brake Light Switch 43
Clutch Lever 43
Switch/Mount 44
Starting Carburettor Lever 44
MZ 125 SXlSM Repair Manual 05/02 1

3.11
3.12
3.13
3.13.1
3.13.2
3.14
3.14.1
3.14.2
3.15
3.16
3.16.1
3.16.2
3.17
3.17.1
3.17.2
3.17.3
3.17.4
3.17.5
3.18
3.18.1
3.18.2
3.18.3
3.18.4
3.19
4
4.1
4.1.1
4.1.2
4.1.3
4.1.4
4.1.5
4.1.6
4.1.7
4.1.8
4.1.9
4.1.10
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
4.3.7
4.3.8
4.3.9
4.3.10
4.3.11
4.3.12
4.3.13
4.4
4.4.1
4.4.2
4.4.3
Table of Contents
Air Filter .. .45
Shock Absorber
.. .46
Foot Rests
.. ..48
Rear Foot Rest .48
Front Foot Rest... .48
Side Stand........
.. ..49
Side Stand Switch 49
Side Stand
.. 50
Intake Muffler
51
Muffler.............................................. .. 52
Exhaust Mount Plate...
.. 53
Manifold .. 54
Cooiing System...... .. 55
Cooiant 55
Radiator Cap 56
Radiator Hoses .. 56
Radiator.......... .. 57
Thermostat.
58
Telescopic Fork 60
Fork Spars
61
Dismantling the Telescopic Fork 62
Fork Bridges..
.. 65
Steering Bearing
.. 66
Swing Fork 69
Brakes and Wheels 71
Brakes Front 71
Front Wheel Brake Adjustment... 72
Brake Fluid 73
Bleeding the Brake System .75
Main Brake Cyiinder . '" to
Inspection Window 7,7
Replacing the Seal SeL 77
Entire Brake Caliper 78
Brake Pads 79
Brake Caliper/Components 80
Brake Hose 81
Front Wheel............................................. . 82
Replacing the Front Wheel 83
Front Brake Disc 85
Wheel Bearing
86
Speedometer Drive 87
Rear Brake 88
Brake Fluid 89
Bleeding the Brake System 91
Storage Tank 92
Hose 92
Brake Hose 93
Adhesive Pads 94
Brake Caliper 94
Brake Caliper/Components 95
Brake Pads 96
Brake Lever 97
Rear Brake Light Switch 99
Main Brake Cylinder 100
Seal Set 100
RearWheel 1
01
Replacing the Rear WheeL 102
Chain Plate and Dog 1
04
Wheel Bearing 105
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4.4.4
4.5
4.5.1
4.5.2
4.5.3
45.4
4.6
4.7
4.7.1
4.7.2
4.7.3
5
5.1
5.2
5.3
5.3.1
5.3.2
5.3.3
5.4
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.4.8
5.5
5.5.1
5.5.2
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.13.1
5.13.2
6
6.1
6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
6.3
6.4
6.4.1
6.4.2
6.4.3
Table of Contents
Brake Disc 106
Chain .107
Chain Maintenance 107
Adjusting the Chain
Siack. .107
Chain Se!........................ .108
Replacing the Chain Slider 109
Tyres 110
Spoke Fitting
111
General Procedure. . . 111
Spoke Fitting Values for SX 111
Spoke Fitting Values for SM 112
Electrical Installation 113
General Principles 113
Fuses.................... .113
Battery 114
Checking the Electrolyte Level 114
Replacing the Battery 115
Charging the Battery .116
Ignition 117
Block Circuit Diagrams .117
Spark Plug............................ .118
Spark Plug Connector with Ignition Cable 119
Ignition Coil. 120
Ignition Box........................... .122
Ignition Box Inspection .123
Conversion
to the 80 km/h Varian!................ .124
Regulator/Rectifier............
.. 125
Alternator .127
Stator. .127
Rotor.......... .128
Flasher Relay 130
Starter Relay......................... .130
Shut-off Relay
131
Thermal Switch 132
Horn 133
Starter .134
Fan 135
Diodes .136
Position and function........ .136
Test Diodes 136
Engine 137
General Information 137
Inspection.... .137
Compression Pressure 137
Oil Level
.. .138
Oil Change 138
Oil Filter 140
Oil Return Plug .
141
Oil Pressure Sensor 141
Checking the Oil Pressure 142
Engine Removal.......................... .142
Clutch .144
Adjustment 144
Clutch Activation Lever. 145
Removing the Clutch 146
MZ 125 SXlSM Repair Manual
05/02 3

I.J.J .. .r j
6.4.4
6.5
6.5.1
6.5.2
6.6
6.6.1
6.6.2
6.6.3
6.7
6.7.1
6.7.2
6.7.3
6.7.4
6.7.5
6.8
6.8.1
6.8.2
6.9
6.9.1
6.9.2
6.9.3
6.9.4
6.9.5
6.9.6
6.10
6.10.1
6.10.2
6.10.3
6.10.4
6.11
6.12
6.12.1
6.12.2
6.12.3
6.12.4
7
Table of Contents
Installation 149
Gearshift....... .150
Selector Shaft 150
Free 'M1eel.
.. . 151
Pumps 152
Oil Pump........... .152
Water Pump...... .153
Oil Pressure Regulator.. .154
Cylinder Head 155
Removal 155
Valve Train 158
Timing Chain, Tension and Guide Rails 158
Chain 'M1eel, Camshaft......................................... .160
Installation
161
Valves.... .163
Valve Seat.
.. .165
Adjusting Valve Clearance 169
Cylinders
171
Removal......................................... . 171
Cylinder Dimensions.... .172
Piston................. .172
Piston Rings 174
Installation.......... .175
Intake Manifold 176
Transmission 177
Removal 177
Inspection .179
Crankshaft and Balance Shaft
181
Installation 182
Engine Installation and Adjustment 183
Carburettor...... .188
Settings 188
Removal 190
Dismantling and Inspecting
191
Installation 193
Index 197
405/02 MZ
125 SXlSM Repair Manual

!..Jjf1
Safety Regulations and Information
1Safety Regulations and Information
1.1 Important Information
Important information in this manual is designated as follows:
DANGER!
Immediate danger!
Failure to heed the warning may result
in serious injury or death.
Attention!
Dangerous situation!
Failure to heed the warning may result in injuries or property damage.
Note:
Useful supplemental information or user tips.
Environment!
Possible dangers for the environment and information on how to prevent them.
.ItiZl Tightening torque:
<ft Special tightening torques to be observed.
Every safety item explains: -which danger exists,
-what can happen,
-what you can do to prevent injuries.
Warning of hazards when handling
batteries Warning against corrosive liquids
AWarning against hazardous voltage
#c!,,':
Warning about flammable materials and
substances
Warnings about the risk
of crushing inju-
ries caused by the driving chain
Danger
of crushing
Warning about hot surfaces
AWarning aboutexplosive substances
MZ 125 SXlSM Repair Manual 05/02 5

u.:.tL1
1.2 Safety Regulations
Safety Regulations and Information
Attention!
Installation errors can endangerthe health or even the life of the vehicle operator and
other persons
in traffic.
For this reason, please observe all safety regulations and information when
performing work.
Work safely and with your full attention! Follow the procedures described in the manual!
Only operate engines in awell ventilated work area and for no longerthan necessary (health and environment!
Use only original replacement parts and accessories from MZ Motorrad- und Zweiradwerk GmbH!
Dispose
of brake fluid, fuel remains and oily rags according to the regulations!
Install the parts using the specified tightening torques!
When working
on the vehicle, secure it against tipping or rolling away!
Observe the BGR 157 safety rules
of the Professional Association of Vehicle Maintenance, WorkshopOrdinance
ZH1/525 and the general regulations as per BGVA1.
1.3 ImportantWork Information
Always de-energize the electrical installation (disconnect the batteries and/or remove the fuses) before starting
any repair on this installation.
•Label all removed parts as necessary in the order in which they were moved. This helps ensure that the parts
are returned to their original locations.
•When working
on the vehicle, protect painted surfaces and seats with a clean cloth or other suitable cover.
•Carefully inspect all parts before removal to determine the purpose ofthe repair.
Use special tools when specified.
When removing multiple screws or nuts, start with the middle or largest screw.
Tighten the screws in crosswise alternation in two or more steps.
1.4 lmpor+.ant Maintenance Instructions
The dealer is responsible for performing the following work in coordination with the vehicle owner to guarantee the
vehicle's operating safety and roadworthiness whenever inspections are made and/or during any unscheduled visit
to aworkshop.
•Replace the brake fluid and the gaskets ofthe brake cylinders and the brake calipers every 2years and after
every repair performed on the brake systems.
Replace the coolant every two years.
Replace the engine oil at the mandatory inspections
or at least once per year.
Replace the brake hoses in case
of damage or cracking or every 4years.
Replace rubber components, fuel and vent hoses in case
of damage or cracking or every 4years.
Replace cooling system hoses in case
of damage or cracking.
605/02 MZ 125
SXJSM Repair Manual