Section 2 Common Sense Of Maintenance - ZONGSHEN ZS125-86 Service Manual

1. Maintenance Classification
According to the broadness of working range and the length of interval time, maintenance work can be
divided into overhaul (heavy repair), medium repair, minor repair and unit repair.
[1.]An overhaul is a thorough comprehensive repair towards the motorcycle, requiring a complete
disassembly, cleaning, inspection, repair or replacement of parts, and assembly and debugging. An
overhaul restores the original performance indicators such as motorcycle power performance, economical
efficiency, reliability and security.
[2.]A medium repair is to mend and adjust the position that affects the usability. A medium repair can
eliminate hidden dangers, to avoid the development of a failure and to maintain a good operating state.
[3.]A minor repair is maintenance of maneuverability, mainly to eliminate temporary faults and local
damages in the operation process.
[4.]A unit repair is adopted to take a separate repair to an assembly due to the damage, abrasion,
deformation, etc. of a certain assembly or a component that affects the usability of the complete motorcycle
2. Repair Process
1)Decomposing the Motorcycle
A decomposition can also be called a disintegration or a disassembly. It is an important link of repair
operations. The correctness of the decomposition method directly affects the quality and efficiency of repair
operations. An improper decomposition may cause parts to be damaged or stuck. It not only expands the
range of repair operations, but also delays the repair period, or even causes a pause to the decomposition.
The basic principle of a decomposition: to disassemble parts in an order and direction inverse to the
assembly, that is, firstly to disassemble those parts that have been assembled latter and then those parts
assembled earlier. In general, it can be conducted in the order from outside to inside, from upside to
downside, and from big to small. In particular, pay Caution to parts storage environment and ordering to
prevent from damages or confusion.
Decomposition order and method is not absolute. According to different models, decomposition
procedures and methods can be different. Refer to the subsequent methods given in respect of demolition,
installation and maintenance.
The engine assembly and other part assemblies are decomposed by the basic principles same to the
decomposition of a complete motorcycle. Due to differences of different part assemblies in structural style
and characteristics, the decomposition procedures and methods are also different. Meanwhile, as a part
assembly is decomposed into scattered parts, so it requires more in respect of storage environment and
ordering.
The following points should be noted in regard to the decomposition of a complete motorcycle and its
part assemblies:
[1.]For a part that expects much in locational fit, fit marks should be checked when the part is being
disassembled. If marks are not clear, it should be re-marked.
[2.]A part with a interference fit should be disassembled by use of special tools. Without special tools,
you can first cushion the part with a wooden or soft metal ware, and then ram it in the right direction and
position with a rubber hammer in the way that prevents the part from damages.
[3.]Front and rear dampers and wheels and other assemblies shall be decomposed when the main
frame is firmly supported, so as to prevent the main frame and parts from being overturned and damaged.
[4.]Decomposed parts should be placed in order of demolition. Painted parts, chromium-plated parts
and high-precision parts should not be directly put on the ground.
[5.]Removed nuts and bolts should be carefully stored, or be equipped to original positions without
being tightened.
[6.]Parts necessary to be removed by use of special tools should be carefully operated. Note the force
evenly exerted and proper direction.
[7.]Parts and components should be decomposed by use of proper tools and attaching importance to
the size and direction of force, so as to avoid damages to parts.
[8.]Removed brake shoes should be placed separately, and are strictly prohibited to contact with
lubricating oil, otherwise it will lead to a brake failure.
[9.]In case of any difficulty in decomposition due to the corrosion of screw elements, soaking the parts

Section 2 Common Sense of Maintenance

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