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Bearings are widely used in various machinery. It can be said that as long as you running a machine, bearings are inseparable. Bearings are key components of motorcycles. For all kinds of bearings, its role is very different.

On motorcycles, ball bearings are generally used in the internal drive train and wheels of the engine, flat ball bearings are used on the front fork, and needle bearings are used on the crankshaft connecting rod and part of the drive gear shaft. Generally speaking, the front wheel of a car under 100cc is 6200.6201.6300.6301. The rear wheel is 6301.125cc. The front wheel of a 150cc car is 6301. The rear wheel is 6202.6302.


62/22.62/28.62/32.63/22.63/28.63/32. It is also more commonly used.


First of all, the durability of various bearings is different. Among them, ball bearings are the most durable. Therefore, motorcycle engine crankshaft bearings, main and countershaft bearings, and front and rear wheel bearings mostly use ball bearings. This kind of bearing has strong impact resistance and is convenient for gear oil. Lubrication means lack of oil lubrication in a short time without excessive wear. Ball bearings are the most durable at both ends of the main and auxiliary shafts of motorcycles. For example, the Tianjin Honda 90 engine has a very low failure rate, and there are very few major repairs due to bearing damage. The main reason is its reasonable design and scientific bearing selection. Therefore, ball bearings are so popular with major machinery manufacturers that they are irreplaceable. Needle roller bearings have other advantages. They are small and compact, and can be rotated with small space components, such as crankshaft small-end needle roller bearings (such as two-stroke motorcycles), C100 countershaft small-end needle roller bearings, and GY6 machine rear wheel output Needle roller bearings for shafts and two-stroke scooter overrunning clutches are matched with needle roller bearings. Bearings in these parts cannot be replaced by other bearings because of the extremely limited space for matching parts. Especially the ultra-thin shim-shaped needle roller bearing on the AX100 transmission gear shaft shows the unique function of the needle bearing, which not only plays the role of shim clearance adjustment, but also solves the relative sliding between the gear and the gear. Got. But the durability of needle roller bearings is not good, especially the big and small needle rollers on the crankshaft of two-stroke motorcycles. If the lubrication is poor, it is easy to lock up. When the copper sleeve replaces the bearing, the durability is worse. The copper sleeve at the right end of the camshaft on the FXD125 cylinder head is easily damaged and difficult to repair when the lubrication is poor. Only the cylinder head can be replaced, which increases the maintenance cost.


Secondly, the sound-absorbing effect of the bearing at the joint of each part has its own merits, especially when the copper sleeve is used instead of the bearing, the combination is soft and the noise is small, so the copper sleeve is still widely used by many motorcycles, such as C100 countershaft small head, DX crankshaft small head For some multi-cylinder engine crankshaft small heads, copper sleeves are used instead of bearings, and the effect is very good.


Third, the impact resistance of various bearings is different. Bearings used in motorcycles must have strong impact resistance in certain key parts, such as two sets of pressure bearings on the steering column of each motorcycle, and ball bearings are the most resistant to impact. When motorcycles are running on bumpy roads, pressure bearings are the most vulnerable to damage, while ball bearings have the best effect, followed by needle bearings. In the motorcycle transmission system, ball bearings are the most durable, followed by needle bearings, and copper sleeves are the least durable. Some motorcycle repairers replace the small-end crankshaft needle with a copper sleeve, mainly because the copper sleeve has a good noise reduction effect. In addition, the needle roller bearings on the main and auxiliary shafts are replaced with copper sleeves. I think it is not advisable, because the transmission mechanism is to transmit torque and output power. How can a soft copper sleeve be competent?


The disassembly and assembly of various bearings is also very knowledgeable.


1. Disassembly and assembly of the bearing on the wheel hub of the vehicle. It is inevitable that the car’s moving bearings will malfunction. If the wheel hub bearing is slightly loose, it can be knocked down and replaced, which is easier. If the ball bearing cage is broken to cause the bearing to “fall apart”, it will be much more difficult to remove the inner and outer circles of the bearing. It is necessary to use electric welding to weld a smaller Fes bearing on the outer circle of the bearing in the hub. After it is cooled, use a hammer and steel to punch it down. The outer circle of the steel bearing on the aluminum hub is easier to heat and cool. Rush down. Don’t use brutally, because most of the wheels are aluminum, and the rims will be cracked and damaged if they are hit hard without proper treatment. Care should be taken when reassembling the bearing here. You must carefully remove the debris on the bearing seat, polish the hub bearing seat with fine sandpaper, apply a proper amount of grease on the outside of the new bearing, and slowly tap the bearing in with a wooden block on the pad , To be in place. The bearings here should be fully enclosed bearings, and sufficient grease must be applied before assembly. The steel sleeve between the two bearings on the wheel hub should not be missing, and the bearings will be easily damaged after missing.


2. Needle roller bearings on the engine. The most headache for maintenance workers is the outer circle of the needle roller bearing on the engine case. After the needle roller bearing is severely worn, only a thin steel sleeve falls in the case, and no special tools can be easily removed. At this time, a thick steel sheet must be welded to the inner wall of the broken needle bearing sleeve by electric welding. After it has cooled, the thick steel sheet can be gently knocked to remove the outer circle of the bearing. After thoroughly cleaning the bearing seat, the new needle roller bearing must be tapped into the bearing seat lightly with a copper rod. Do not use excessive force to prevent damage to the new needle roller bearing. The needle roller bearings on the upper back must be moved with your fingers, and the sliding needles must slide smoothly and freely.


  1. The bearing on the crankshaft. Due to the congenital design defects and poor lubrication, the bearings at both ends of the crankshaft are easily damaged. When opening the middle box to replace the crankshaft bearing, if the bearing falls on the box body, it is easier to replace it. If the bearing falls on the crankshaft, the replacement is more troublesome. At this time, gas welding can be used to evenly heat the worn bearings for 3 minutes, and then use flat steel to pry off the bearings easily. The new bearing should be smeared with a proper amount of lubricating oil and installed on the box body, and then the crankshaft should be installed to make it easier to fit the box.

Post time: Nov-25-2021