1. How to disassemble the rear trunk of the motorcycle
First open the lock of the trunk, and then you can see the installation screws at the bottom of the trunk, and you can remove the screws Remove the trunk. There are also some tail boxes that are stuck on the mounting bracket with clips. Generally, after the tail box lock is opened, it can be removed from the bracket with a button or knob.
Second, what should I do about the abnormal noise in the trunk of the motorcycle
The abnormal noise is actually because of the gap. It is recommended to find something thinner like a sponge and plug it when closing the tail box, so that it can play a role of filling and buffering.
Three.Various strange noises and abnormal noises of motorcycles, diagnosis, detection and repair
(1) Disc brakes Solution to Abnormal Noise
Reason: If your motorcycle makes a rattling sound when the brake pads hit the iron when crossing a pit or vibrating, it must be a disc brake problem.
Solution:
1. Prepare the cap to unscrew the screw, and turn it at the inner 6 corner of No. 5.
2. Use the No. 5 hexagonal wrench to loosen the brake pad fixing screw, and then unscrew the caliper fixing screw.
3. Remove the brake pad and see the limit shrapnel of the brake pad. This shrapnel is embedded in the caliper. Pay attention to the buckle on the side. Pull it out by hand or flatten it out. Can.
4. Take out the shrapnel and use needle-nose pliers to slightly tilt the arc of the shrapnel upwards.
5. The arc that can be tilted is larger, so that the brake pads with large pits or large vibrations will not sound.
6. Then observe the brake pad fixing screw, if it is smooth to the touch, generally long-term braking, the screw always feels a bit astringent.
7. Slightly smooth with fine sandpaper, apply butter, and then put the brake pads, because the camber is too large to press the brake pads by hand.
8. Insert the fixing screw of the brake pad. Put it back as it is. Finally, stick the set screw with some butter and tighten it.
9. After installation, press and release the brake until it returns to the original position.
10. Test the car, find a pit to ride it, and feel the troubles of no ding ding ding dang.
(2) Abnormal noise in the rear brake
Reason: The abnormal noise when the motorcycle steps on the rear brake is very harsh, like friction between metals, what is the reason?
Most of these sounds are caused by water or dust in the brake hub, which will not affect the brakes. Please also note that the excessive wear of the asbestos layer on the brake pads can also cause this problem. Phenomenon, if this is the case for a long time, it is recommended to replace the brake pads. In any case, safety is the first, and the reason for the noise may be caused by the following problems:
1. The quality of the brake pads is not good enough.
2. If there is any foreign object on the brake device, there will also be noise at this time.
3. The brake disc or brake pad is deformed and has been impacted by external force. Many times the eyes cannot see the subtle deformation, and it will make a harsh sound when it is used.
4. There will be a sound when the air humidity reaches a certain level. This sound can be tolerated by people. After running for a while, when the water vapor on the brake pads is gone, it will not make much noise or no sound.
5. You are the asbestos dust produced by the wear of the brake pads. The pressure and temperature of the brake pads form a hard enamel on the surface of the brake pads when they are sandwiched between the brake pads and the hub. Make a harsh sound.
Solution: Use a saw to cut several grooves on the friction surface of the brake pad, so that there is a swirling airflow in the brake drum when braking. The dust of the brake pad enters the groove and is swept by the airflow. opened. You must replace the white-colored brake pads, which are hard brake pads. There is absolutely no problem if you change to a red-colored soft brake pad with grooves.
Suggestion: Brake pads are wearing parts, which are generally out of warranty. They can only be replaced unless there are quality problems, such as fractures caused by steel fire problems, and wear too fast (the normal wear level of 3 months, a month) and so on.
(3) Abnormal sound of engine
When the engine is working, the normal sound will be mixed with the abnormal sound. What’s more, there are many types of vehicle engines. However, as long as you fully understand the causes of different types of abnormal noises in the engine, familiarize yourself with the sounding parts, characteristics, timing and changing laws of various types of abnormal noises, and pay attention to accumulating experience, you can still accurately judge and determine abnormal noises. nature, location and cause.
1. The sound of connecting rod big end bearing
The reason for the sound of the connecting rod big end bearing caused by the sound of the motorcycle connecting rod big end bearing is usually: (using Sliding bearing) connecting rod bushes and chain journals are poorly matched, (using rolling bearings) bearings are poorly worn, burnt due to poor lubrication, over-tight bearing bushing, improper operation during repair or poor bearing bush quality and early wear, bearing balls (column) wear, at the moment when the engine works, they collide with each other to produce sound.
The sound characteristics of the connecting rod big end bearing: the sound does not change with the engine temperature. When suddenly accelerating (from idling to medium speed), there is an obvious continuous percussion sound (the rolling bearing is accompanied by abnormal sound inside the engine), which is The main feature of the sound of the connecting rod big end bearing is that when the connecting rod big end bearing is seriously worn (loose), there will be obvious noise when the engine is idling, and the sound will increase when the load is increased.
2. Valve spring knocking sound
The reason for the valve knocking sound is usually: excessive valve clearance and cam wear, change of profile curve, The valve spring is broken. When the engine is working, the broken valve springs collide with each other to produce a sound. The characteristic of the valve spring knocking sound is that the metal knocking sound is continuous and messy. When the engine is out of fire, the knocking sound is almost unchanged. There is a “dangdang” sound when the piston top hits the valve, and a “chacha” sound after the side-mounted valve spring is broken. The frequency of the knocking sound increases with the increase of the engine speed, but the volume does not change significantly.
3. Piston knocking sound
The reason for the piston knocking sound is usually that the fitting clearance between the piston and the cylinder is too large, and the sound of the piston is too large when the engine works. In an instant, the piston is under the pressure of high-pressure gas, swinging and hitting the cylinder wall in the cylinder, producing sound. In addition, the piston is reversely elliptical, the connecting rod is bent or twisted, and the piston pin and the connecting rod copper sleeve (bearing) The connecting rod big end bearing passes through. When tight, it will also cause the piston to knock the cylinder.
After the engine is out of fire, the knocking sound is weakened or even disappears. When the engine is idling, the knocking sound is clear. When the engine is cold, the knocking sound is obvious. After the temperature rises, the knocking sound weakens or even disappears. Inject a small amount (about 3 mL) of engine lubricating oil into the cylinder from the spark plug hole, and slowly depress the starter rod to drive the crankshaft to rotate for about 1 minute, so that the lubricating oil flows into the space between the piston and the cylinder. .
The reason for the knocking sound of the piston pin is usually: the piston pin and the connecting rod copper sleeve (the connecting rod bearing itself) or the piston pin seat hole do not fit well. When the engine is working, the piston pin hits up and down. The copper sleeve (bearing) of the connecting rod or the hole of the piston pin seat produces a percussion sound. When the engine is idling and working at medium speed, the percussion sound is clear, and the frequency of the percussion sound increases with the increase of the engine speed. , After the engine temperature rises, the knocking sound does not weaken, and sometimes it is more obvious (this is obviously different from the knocking sound of the piston). When the fire is cut off, the knocking sound is weakened or even disappears. Obvious 1 (click) or continuous 2 (click) percussion sound;
The reason for the sound of piston ring leakage is usually: the piston ring is not sealed with the cylinder wall, and the moment the engine works , the high-pressure gas broke into the crankcase and made a sound, and the sound of serious leakage of the piston ring was similar to the “knocking sound”. For 4-stroke engines, the sound decreases when the dipstick (filler cap) is removed.
4. Knocking sound caused by detonation
When the engine accelerates suddenly or the motorcycle goes uphill, there is a continuous sharp “click” sound inside the cylinder , which is the knocking sound caused by deflagration. The knocking sound caused by deflagration is similar to the sound produced by the excessive clearance between the piston pin and the small end bushing of the connecting rod. However, the knocking sound caused by deflagration does not occur at idle speed, and you cannot hear the sound when you step on the start lever before starting. After starting, the sound from the piston pin is continuous and messy, while the knocking sound caused by deflagration increases the load and It is most obvious when going uphill, and the sound is crisper.
The causes of deflagration are: engine overheating, excessive carbon deposition in the combustion chamber, low calorific value of spark plug, use of gasoline with low octane number, and premature ignition time.
5. Exhaust pipe blasting sound
Exhaust pipe blasting sound also occurs in two cases, one is due to poor engine operation, The combustible mixture burns and explodes in the exhaust pipe and emits a “pop” sound, which is crisp and loud, and emits sparks or thick smoke at the same time. The sound is weak, cluttered and uninterrupted.
In the former case, the reason for the exhaust pipe blasting is: the mixture is too rich, the ignition time is too late, the gasoline is deteriorated or has moisture, the capacitor is damaged, the exhaust valve of the four-stroke engine is seized or the valve No gaps.
The blasting sound caused by the rupture of the muffler generally can only be re-welded. If the opening at the tail of the muffler is too large, pliers can be used to close the opening a little.
The abnormal noise of motorcycles can also be avoided to some extent. As long as every motorcycle lover maintains it regularly and checks it frequently, the situations mentioned above will not appear to us so quickly…
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