Precautions for motorcycle maintenance
(1) The operating environment should be dust-proof and wind-proof, and the operation should be standardized
Some motorcycle repair shops overhaul engines are operated outdoors. No matter how big the dust is, just worry about changing parts. You don’t know, the dust mixed into the engine will cause undue abrasive wear. The new engine oil changed in this environment may be dirtier than the old engine oil, and the overhaul of the engine must be carried out indoors. In addition, the operation should be standardized. If the CC125 transmission cam and shift fork are replaced, the transmission mechanism can be replaced without opening the left case of the engine and removing the crankshaft. If the operation is wrong, it will cause unnecessary trouble, not only the delay in work and time, but also the poor sealing of the side box. The prerequisite for repairing the engine is to know it well and to understand the structure diagram of the engine parts carefully.
(2) The engine casing must be cleaned before dismantling.
There is a lot of oil and sand accumulation on the engine casing during overhaul. If it is not cleaned in time, These impurities will definitely be mixed into the inside of the body when the engine is disassembled, and after the engine is installed, it will bring unnecessary wear and tear to related components. In addition, foreign objects falling into the engine will block the oil passages, which will lead to poor lubrication, resulting in cylinder holding, shaft holding, clutch sintering, etc. In addition, when the uncleaned engine casing is closed, foreign objects will be stuck at the joint of the casing, affecting the sealing and causing oil leakage and oil leakage. Cleaning the engine casing can also prevent sludge from covering the bolts, so as not to leak. For example, there are two fixing bolts in the middle box of Chongqing 80 engine, which are easily covered by sludge.
(3) Marking is very important
Whether it is a mature model or a transitional model, there are many types of motorcycle engines with different structural characteristics. When we disassemble various engines, we should do the installation marks of various accessories. Some nut threads are the same, but the appearance is very different. They should be marked and not installed arbitrarily, because all kinds of nuts have certain torque requirements. Various shapes are determined by many tests and have certain scientific basis. If they are interchanged, it will affect their fixing effect and cause new failures. For example, the CG125 clutch fixing nut and the oil filter nut at the right end of the crankshaft have the same internal thread, although they can be installed after being interchanged, but the two have different shapes and torques. The torque of the clutch fixing nut is much larger than that of the crankshaft fixing nut. When we disassemble the engines of unfamiliar models, such as CB125T, CBR400, etc., we should mark the disassembled parts to prevent wrong installation and missing installation.
(4) Use special tools and utensils
The use of tools directly affects the quality and efficiency of maintenance work. The special tool is designed for the maintenance of the specified parts, which is scientific and easy to use, saves labor, and does not hurt the accessories. If you are afraid of trouble and save money, any illegal operation of any tool will greatly reduce the quality of the work. For example, after removing the GY6 machine, the clutch fixing nut can be removed smoothly by using a 19# socket wrench and the brake. It can be seen that some repair shops do not have special tools, just use a steel punch to savagely remove the nut. The nut is removed and deformed. How can it be tightened according to the specified torque? Loosening of the clutch fixing nut over time will cause the clutch assembly to fall off, with disastrous consequences. Not long after the overhaul of the motorcycle of a former motorcycle friend, the clutch fell off and the side box broke. Improper operation can also damage the bearing on the inner end of the output shaft.
In addition, when we disassemble the engine, the parts before and after cleaning should be placed in a special aluminum tray or wooden tray in order, and cannot be stacked anywhere. Some small parts are easily lost. , such as semi-circular keys of each crankshaft, piston pin retaining rings, various circlip gasket positioning pins, etc.
(5) Arrangement of parts in order
When disassembling an unfamiliar engine, place all parts in order to prevent missing installation, wrongly installed. For example, for the gear shifting mechanism of each vehicle, when replacing damaged parts, place the disassembled parts one by one from left to right, and assemble them in reverse order after replacing the new ones to avoid mistakes.
(6) The cleaning of related parts is very important
Once the engine is disassembled, the gaskets (paper, asbestos and other gaskets) will be damaged after use. Push the elastic force, push the sealing effect, can no longer be used, should be completely eradicated and replaced with new products. In addition, the sealing parts without gaskets should be carefully removed with bamboo chips to remove the failed sealant (the middle box of DX100, AX100, K100 and other two-stroke engines), and then evenly apply the genuine special sealing glue to the box to tighten. Sludge and grinding should be thoroughly removed from the dismantled parts and the gaps between the parts, such as the hard impurities in the CG125 oil filter and the C100 clutch. This work also determines the use of the engine after the overhaul. Some maintenance workers just replace the damaged parts without replacing the tired oil seals, gaskets, circlips, or cleaning the sludge and impurities in the machine. After the machine is installed and put on the shelves, although the car can be ridden, it will not take a long time, and new failures will appear.
(7) Carefully measure and compare the replacement parts
The parts market is mixed. Seriously compare with new parts and use special tools to actually measure, requiring the engine after overhaul to be in good condition. For example, when replacing crankshafts, cylinder assemblies and other parts, use vernier calipers to measure whether each part of the crankshaft assembly is standard, and measure whether the cylinder plug rings are tightly matched, so as to avoid faults and time-consuming work and time-consuming when the parts are assembled and tested.
(8) The application of lubricating oil for assembly of mechanical parts is indispensable
When assembling and disassembling each piece, take an appropriate amount of new lubricating oil and apply it evenly to each piece The joint parts, such as between the crankshaft and the bearing, the shifting cam and the box, the shifting gear and the gear, the cylinder plug ring, etc., will be more smoothly assembled by applying lubricating oil, so as to facilitate the tight closing of the box and avoid the dryness of the assembled parts. Astringent, difficult to close the box, resulting in damage to the parts.
Motorcycle maintenance attention to detail points
(1) When the engine is disassembled, drain the oil;
(2) Do not allow dust and sludge to enter the engine, and do not use compressed air;
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(3) The oil can only be drained when it is warm;
(4) When installing the spark plug, first tighten it with your fingers, and then tighten it with the spark plug wrench;
(5) The inspection of the valve clearance should be carried out in a cold state (the cylinder temperature is lower than 35 degrees);
(6) When adjusting the chain, the scales of the signs on both sides should be consistent;
(7) When the chain is installed, the opening direction of the chain clip should be opposite to the direction of movement of the chain;
(8) When the battery is replenished, distilled water should be added;
(9) The tire pressure should be checked when it is cold;
(10) The replacement of various lacing lines does not hinder the rotation of the handlebar;
(11) During the spark plug flashover test, be careful not to have any The gasoline leaks or is too close to the fuel tank;
(12) The lock nut of the fuel tank switch cannot be over-tightened;
(13) When adjusting the idling speed, the screw should not be rotated through minutes to avoid damage Nail holder;
(14) When disassembling and assembling the valve lock clip, do not compress the valve spring too much;
(15) When using the hinge, apply cutting oil;
(16) Generally, the valve should not be placed on the ground;
(17) When the valve is repaired, not only should pay attention to the tightness, but also the position and width of the contact;
(18) The outer diameter of the piston is generally measured at 10mm from the bottom;
(19) When the piston ring is installed, the top ring and the second ring cannot be reversed;
(20) When installing the piston ring, do not scratch the piston;
(21) When assembling the engine, do not block each oil hole;
(22) Disassemble the piston pin once, and try to use a new piston Pin retaining ring;
(23) The piston pin retaining ring generally cannot be aligned with the piston opening;
(24) When the bearing is installed, the sealing end should generally face outward;
(25) No lubricating oil is allowed during brake maintenance;
(26) When the wheel is installed, the odometer boss should be aligned with the groove in the wheel hub;
(27) When installing the standpipe nut, first adjust the nut and tighten it to the end, and then return it to 45 degrees, generally to make the free clearance appropriate;
(28) The bearing should not be inclined when it is pressed in;
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(29) The temperature of the battery should not exceed 45 degrees when charging;
(30) When charging the battery, pay attention to ventilation to prevent sparks and open flames.
(31) Seals and cotter pins should generally be replaced after disassembly and assembly;
(32) After disassembly and inspection of engine and transmission parts, apply lubricating oil on the surface to prevent rusting ;
(33) Tighten the nuts and bolts, and apply the crisscross method to tighten them to the given torque value;
(34) When installing the parts, pay attention to adding Corresponding assembly lubricants;
(35) When two people work together, pay attention to each other’s safety;
(36) Use special and general tools as required;
(37) Try to use parts approved by the manufacturer.
