Engine for a motorcycle,

Is "heart" like being,

When the engine fails,

When repairs are needed,

We must be careful,

There are some precautions we need to know in advance.

1, pay attention to the environment and operating standards

Some motorcycle repair shops overhaul the engine in the outdoor operation, they no matter how big the dust, only to change the head. You do not know, dust mixed into the machine will cause undue abrasive wear, in this environment for new oil may be dirty than the old oil, overhaul engine must be carried out indoors.

In addition, the operation should be standardized, the demolition of the demolition, should not move do not move. If the CC125 shift CAM and shift fork are replaced, the left engine box does not have to be opened, and the crankshaft does not have to be removed, the shift mechanism can be replaced and repaired. If the wrong operation will cause unnecessary trouble, not only the wrong time, but also may cause poor sealing of the side box. The prerequisite for repairing the engine is to know it well and carefully understand the structure diagram of the engine parts.

2, pay attention to cleaning the shell

There are a lot of oil and dust accumulation on the engine housing during overhaul, if not cleaned up in time, these impurities will be mixed into the body when disassembling the engine, and bring unnecessary wear to the relevant parts after installation. In addition, foreign matter falls into the engine, it will block the oil passage, and it will lead to poor lubrication, resulting in cylinder holding, shaft holding, clutch sintering, etc.

In addition, when the engine casing is not cleaned, foreign matter will be stuck at the joint of the box, affecting the sealing, resulting in oil leakage and oil leakage. Cleaning the engine housing can also prevent the sludge from covering the bolts, so as to avoid leakage. Such as Chongqing 80 engine box fixing bolts, there are two easy to be covered by mud, if missing, forced to remove the box, will damage the engine box.

3, do a good job of waterproof work

The wiring harness connected to the engine should be plugged into the position to do waterproof and rainproof work. After the engine is installed on the large frame, the wiring harness should be straightened out, and the plug should not be leaked to ensure that the lighting charging line works normally. In addition, the waterproof sleeve should be installed firmly, the wiring harness is stuck, and the waterproof tape should be tightly wrapped without the waterproof sleeve.

4. Make marks and place them in an orderly manner

Whether it is a mature model or a transitional model, there are a wide variety of motorcycle engines with different structural characteristics. When we decompose various engines, we should do a good job of the installation of various accessories, some nut wire is the same, but the appearance is different, should be marked, can not be arbitrarily installed, because all kinds of nuts have a certain torque requirements, various shapes are determined after many tests, there is a certain scientific basis, if exchanged, will affect its fixed effect, lead to new failures.

When disassembling unfamiliar engines, the parts should be placed in sequence to prevent leakage and misinstallation. Such as the engine shift mechanism of each car, when replacing the damaged parts, the decomposed parts are placed one by one from left to right, and the new products are assembled in the opposite order to avoid mistakes.

For example, CG125 clutch fixing nut and crankshaft right end oil filter nut have the same internal thread, although they can be installed after interchange, but the two shapes are different, the torque is different, and the clutch fixing nut has much greater torque than the crankshaft fixing nut. When we disassemble the engine of less familiar models, such as CB125T, CBR400, etc., we should make marks on each piece to prevent wrong installation and missing installation.

5. Use special tools

The use of tools directly affects the quality and efficiency of maintenance work. Special tools are designed for the maintenance of the specified parts, scientific and easy to use, labor-saving, do not hurt parts, such as afraid of trouble, to save money, just take a tool illegal operation will make the quality of work greatly reduced.

For example, after removing the clutch fixing nut of the GY6 machine, the 19# socket wrench can be successfully removed with the brake. It can be seen that some repair shops do not have special tools, and they can take a steel to remove the nut, and the nut is removed, and how can the deformed nut be tightened according to the specified torque?

Clutch fixing nut loose for a long time will cause the clutch assembly to fall off, the consequences are unimaginable.

After a motorcycle overhaul, the clutch came off and caused the side box to break. Irregular operation can also damage the inner bearing of the output shaft.

In addition, when we disassemble the engine, the parts before and after cleaning should be placed in a special aluminum plate or wood plate in order, and can not be stacked anywhere, some small parts are easy to lose, such as the semicircles of the crankshaft, the piston pin stop ring, and various spring gasket positioning pins.

6, cleaning parts is critical

Once the engine is disassembled, the gaskets (paper, asbestos and other gaskets) will push the elasticity and promote the sealing effect after use, and can no longer be used, and the new products should be completely removed and replaced. In addition, the gasketless sealing part should be carefully removed with bamboo pieces of failed sealant (DX100, AX100, K100 and other two-stroke engine boxes), and then evenly apply genuine special sealing adhesive box fastening.

The oil mud and grinding bamboo pieces of the removed parts and the machine parts with the gap are completely removed, such as the hard debris in the CG125 oil filter and C100 clutch. This work also determines the use of engine orders after overhaul. Some maintenance workers only replace the damaged parts, do not replace the tired oil seal, gasket, spring, and do not clean the mud and impurities in the machine, after the installation of the machine, although the car can ride, but the time is not long, new faults will appear.

7, the assembly of parts must be lubricating oil

When assembling the disassembled parts, appropriate amount of new lubricating oil should be evenly applied to the combined parts of each part. For example, between crankshaft and bearing, shift CAM and box, shift gear and gear, cylinder plug ring and other parts, grease assembly will be more smooth, to facilitate the tightness of the box, to avoid the assembly of each part dry, difficult to close the box, resulting in damage to the parts.

8, the selection of standard gaskets, careful use of sealant

When assembling the engine, the selection of new gaskets can not be ignored, if the selection of non-standard gaskets, will cause oil leakage, starting difficulties (two-stroke car air leakage, resulting in too sparse mixture, so difficult to get the car), even more will cause oil circuit obstruction, resulting in new failures.

Especially the upper cylinder pad, the requirements are strict, the defective products are easy to burn through, the asbestos can not be used aluminum pad, too thick will affect the compression ratio, resulting in the vehicle is difficult to start, driving is weak. In addition, it is also necessary to pay attention to the rubber gasket, sealing ring can not be leaked, such as CY80, DX100, AX100 and other crankshaft rubber ring, carburetor interface rubber ring.

Sealant is rarely used in engine assembly, only in the two-stroke car box assembly, CB machine cylinder head will be used, four-stroke car engine assembly generally do not need to apply a drop of sealant, such as C100, CG125, CG150, GY6 and other machine joints of the gasket, rubber ring can be sealed very well.

Although the sealant is conducive to sealing, more sealant will block the oil circuit and cause new failures.

If the sealant is applied at the joint of the rubber ring, the rubber ring will be glued to death and the sealing effect will be lost, such as CG125 and GY6 cylinder head.

9, pay attention to replace the oil seal

When the engine is overhauled, the relevant oil seals after disassembly will have different degrees of operation, and the new products should be properly replaced to prevent oil leakage or mixture leakage, resulting in start-up difficulties. Individual large displacement motorcycle or special motorcycle oil seal is difficult to buy, if the original car oil seal operation is not large, you can remove the spring of the oil seal lip, cut about 5mm, you can use as usual.

10, careful assembly

I have seen the motorcycle engine after many overrepairs, the fixed parts are not less this, is missing that, for example: the engine and the flexible combination of steel rubber sleeve leakage, will cause the engine resonance, the driver feels very uncomfortable, and even cause driving danger. Chongqing 80, Jetta 100, Jincheng 90, etc., are all of this structure. In addition, the flat pad and spring gasket on the engine fixing bolt are missed, and the engine will be loosened for a long time, affecting driving safety.

On the general electric starting motorcycle, there is a thick wire between the engine and the big frame, and both ends must be solid to avoid virtual connection, otherwise, it will cause the starting motor to work weak and start difficult.

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