What are the symptoms of a loose valve on a motorcycle?

1.As long as the valve clearance is not suitable, it can be adjusted at any time, and it can generally be adjusted at one time, and there is no need to adjust it repeatedly.

2.Formal adjustment, need to use the feeler gauge to measure, the general valve clearance according to the model is different, the clearance is on the left and right, the scooter can be larger, but this is more troublesome, so generally in the maintenance is to feel by hand with experience, left and right smooth clearance, up and down without clearance, but some cars will be equipped with a spring or spring pad to eliminate the gap on the valve rocker arm shaft, so it may not feel obvious.

3.The valve clearance must be adjusted to normal, too large or too small is not good, let alone artificial faults can not be adjusted up or small, too large and too small have only disadvantages, no advantages.

4.The valve clearance must be adjusted when the car is cold, and the valve clearance will change when the car is hot, and it should be based on the cold state. If you feel that the power decreases and is accompanied by unstable idling after adjustment, the gap should be smaller, which should be adjusted in time, otherwise it will not only affect the normal use, but also the valve clearance will increase the pressure load of the rocker arm and camshaft and increase wear.

However, if the car is a top rod engine, it is inevitable that the valve sound of the hot car will be too loud, so there is no need to pursue too low sound.

If the valve clearance is too large, the valve opening will be smaller, the opening time will be short, and the inflation will be insufficient. Poor exhaust reduces engine power. [Powerless].

It's just that when the speed is not high, there is a clicking sound, that is, the valve is loose, and it will not affect the others.

will affect the dynamics. If the valve is tightened, the clearance is too small, which will cause the valve to be closed loosely, resulting in difficulty in cold starting, unstable idle speed and easy stalling, carbon accumulation at the valve, excessive pressure between the valve rocker arm and the camshaft and poor lubrication, and the rocker arm and camshaft are worn out.

The role of the valve is to be responsible for inputting air into the engine and expelling the exhaust gases after combustion. In terms of engine structure, it is divided into intake valve and exhaust valve. The function of the intake valve is to draw air into the engine and mix it with fuel for combustion; The function of the exhaust valve is to exhaust the exhaust gases after combustion and dissipate heat.

Extended information: Status: In order to improve the efficiency of intake and exhaust, multi-valve technology is now mostly used, and it is common for each cylinder to be arranged with 4 valves (there are also 3 or 5 valves for a single cylinder, the principle is the same, such as the engine of Audi A6), 4 cylinders are a total of 16 valves, and the "16V" we often see in the car information means that the engine has a total of 16 valves.

This multi-valve structure is easy to form a compact combustion chamber, and the injectors are arranged in the first place, which can make the oil-gas mixture burn more quickly and evenly, and the weight and opening of each valve are appropriately reduced, so that the valve opening or closing speed is faster.

Material: The material of the valve is usually divided into 40Cr, 4Cr9Si, Cr10Si2Mo, 21-4N and 23-8N in China. 5Cr8Si, CR9Si -2N, 21-12N, 23-8N, XB, etc. have been used in large quantities on some imported models.

High-temperature nickel-based alloys have also been applied to the exhaust valves of high-load diesel engines. Hope.

After the valve clearance of the motorcycle engine is adjusted, there will still be a clicking sound, which may be that the valve rocker arm and camshaft have been worn out and grinded out of the pit, so it is useless to adjust the valve clearance, and the valve rocker arm and camshaft need to be replaced. However, it is also possible that this clattering sound is not caused by the large valve clearance, but due to other faults, so it is useless to adjust the valve clearance, and it is necessary to find the real cause of the failure and eliminate it.

There are many reasons why a motorcycle engine can rattle and rattle, and excessive valve clearance is just one of them. If you listen to the sound to judge that it is emitted by the valve part, first check whether the valve clearance is too large, if the clearance is too large, you can adjust it correctly first, if you confirm that the adjustment method is correct, there is still a sound similar to the large valve clearance, then it is very likely that the valve rocker arm and camshaft have been worn out, you need to remove them to check it, if it is really worn out, you have to replace it with a new one.

Other faults that can cause a large rattle sound such as a large valve clearance, as well as the timing chain lengthening or its tensioner failure (only for chain engine engines), excessive contact and knocking of the cylinder due to wear of the cylinder, piston and piston rings, excessive carbon deposits in the engine, and poor gasoline or oil quality may sometimes cause such a sound. The engine is composed of many parts, and many of these parts are running at high speed and high temperature, so many parts have problems, which may cause a clattering sound, and some are not faults, but they cannot be eliminated, but they will not continue to expand and cause the sound of failure, if so, don't worry about him.

If the valve is too tight, it will affect the power, and it is not good to start the car, and if it is serious, it will push the valve.

1. The working slope of the valve and valve seat ring.

abrasion, ablation, spotting or denting, carbon deposits;

2. The gap between the valve stem and the valve guide is too large, the valve stem is shaking, or the valve stem is bent, and the valve head is skewed, resulting in the valve closing is not tight;

3. The elasticity of the valve spring is weakened and the elasticity is lost, or the spring is broken, resulting in the inability to fit closely between the valve and the valve seat;

4. The valve clearance is small, and after the valve stem is heated and expanded, the tappet and rocker arm open the valve, so that the valve cannot be completely closed and leaks, making a spike sound;

5. The abnormal noise between the end face of the valve stem and the tappet adjustment bolt is due to improper adjustment of the valve clearance.

Motorcycle valve adjustment.

Before adjusting the valve, it is necessary to make sure that the piston is in the top dead center position, and the new car can refer to the T line, turn the magneto counterclockwise to make the observation hole align with the "T" line, and then determine that the intake and exhaust valves have axial directions.

(adjust the coaxial orientation of the bolt) to determine the correct position.

The old car must press the starting lever and observe and experience with the leather car eye. Because only when the rocker arm reaches the top dead center, the valve can adjust the clearance, and the rest of the positions have springs to automatically lock the valves, that is, if the valve clearance is loosened when it is not at the top dead center, the spring will automatically compress the valve clearance.

Feeler gauge. It is a theoretical data, choose a feeler gauge with a specified thickness, insert it into the valve gap and pull it back and forth, if you feel a slight resistance, the clearance is appropriate, if not, it means that you need to adjust.

However, it is very inconvenient to use a feeler gauge in actual operation, that is, when the nut is loose, the screw is screwed, and then the feeler gauge, the loose screw may be misoperated and guessed to move by itself.

1. Abnormal valve noise, the valve clearance is too large, and the most likely thing is abnormal noise, which mainly comes from the collision between the rocker arm and the valve, and it needs to be adjusted in time.

2. The main reason for the decline in power after the valve clearance is too large is that the intake and exhaust volume will decrease, which is mainly because the opening of the valve will become smaller, which will affect the intake and exhaust volume of the engine.

3. After accidental damage and the valve clearance is too tight, if it is not adjusted in time, for the ejector rod engine, there will be the possibility of causing the ejector rod to fall off, because the ejector rod relies on the upper and lower rocker arms for positioning, and if the gap is too large, the ejector rod will be displaced, and then it will fall off.

The valve is too tight because the valve spring is more elastic than usual, which generally only increases valve wear, and nothing else

The synergy of the main power! You pushed the box without taking into account the gravity of the box.

The valve is leaking, the compression ratio is reduced, and the hot car is not easy to start without idling, stalling or stalling.

The car is sluggish, easy to stall, and accelerates valve wear.

Summary. The reason for the poor start of the cold car is that the valve leaks to accelerate, the weak steel ring gap is large or the engine oil is burned, etc., which will cause the cylinder pressure to be too low and it is difficult to start, and the replacement of better quality engine oil can alleviate this problem in the case of low temperature.

In addition, after tens of thousands of kilometers of motorcycles, the engine performance declines, and the internal parts are seriously worn, especially the cylinder pistons, piston rings, etc., which will also lead to the difficulty of cold start of the motorcycle, if this is the case, the engine must be repaired, and some parts must be replaced if necessary.

1. Will the valve become tighter or looser during long-term use of the motorcycle? What is the reason?

Hello, don't worry, I can ask for your question, but wait a minute, I need text for about 2 minutes.

Hello, I am your exclusive technician, attentive and attentive to solve the vehicle problems for your car, for you to find solutions and methods that will affect the power of the valve tightening, the gap is too small will cause the valve to close, not strict caused by the difficulty of cold start, unstable idling, has turned off the gas door, carbon deposition valve rocker arm and cam hole between the round shaft pressure is too large and poor lubrication, so that the rocker arm and camshaft wear, the role of the valve is specifically responsible for the air input to the Natsu collapse engine and discharge the exhaust gas after combustion.

It's just that it's hard to start when it's cold, and it's no problem to drive on the road after starting.

The reason for the cold car is that the valve leaks and slips to accelerate, the weak steel ring gap is large or the oil is burned, etc., which will cause the cylinder to be too low pressure to start difficult, in the case of a relatively low temperature to replace the better quality of the engine oil can alleviate this problem, in addition to the motorcycle after tens of thousands of kilometers, the engine performance declines, the internal parts wear is serious, especially the cylinder piston piston, piston ring, etc. will also lead to the difficulty of the motorcycle cold start, if this is the case, the engine must be repaired. Some parts must be replaced if necessary.

If the valve is sent, it will cause the valve to leak, and the car will be difficult to start or even not start at all when the valve is leaking, and it will be easy to idle and stall and lack of power when it is barely started. The carburetor will back-spray when the intake valve is leaking, and the exhaust pipe will be discharged when the exhaust valve is leaking.

Adjust it in the following way.

Measured with a feeler gauge, the general valve clearance is different according to the model, the clearance is on the left and right, and the scooter can be larger, but this is more troublesome, so it is generally used to feel the destruction of the light by hand with experience during maintenance, and the left and right are smooth and have a spring gap between the keys, and there is no gap between the top and bottom.