Motorcycle Fault Judged By Color Of Exhaust

Motorcycle enrich our life, make it quickly and easily and expand our space. But if you didn’t maintain the motorcycle well, it will also bring the rider endless trouble and unnecessary economic losses. If your motorcycle release colored exhaust when running on a flat road, it might have been under serious illness. But you don’t need to be panic, stop the motorcycle and watch the color of the exhaust. If exhaust is colorless or slightly white, this suggests that your motorcycle is absolutely healthy. If the exhaust is black, blue or rich white, then there is maybe some problem with the motorcycle. If the exhaust is colorful or even there is dark smoke, then there is something wrong with the engine and you need to figure out the reason and repair it.The black exhaust

Black seems to be a depressing color. The reason should be rich mixture. That is to say, the mixture of gas in cylinder component is beyond the normal level. The incomplete combustion gas in the combustion chamber cause the carbon particle exhausted with the waste gas.Failure is likely to come from the following reason:

• Air filter is blocked so there is not enough air input.

• There is some problem with motorcycle sprocket, like idling air inlet congestion, then the air input is not enough.

• The oil level of float chamber is too high, some gasoline go directly into the cylinder without atomization, which will cause incomplete combustion.

• Main orifice wearout seriously and then the fuel injection from primary nozzle increases, which will cause incomplete combustion.

• Heating automatic valve is in start position and the enrich valve can’t be closed automatically, which will caused a rich mixture.

•     Carbon deposit in muffler, exhaust jam, waste gas stay in cylinder, which will caused incomplete combustion and then black smoke.

If the above failure is not eliminated promptly, that will lead to carbon deposit at air valve, influnce the sealing of the combustion chamber, decrease the engine power and low the speed. You should stop the motorcylce immediately and clear the trouble.Then you can follow the steps below:

• Check whether the air cleaner is blocked or not.

• If the filter element is made of paper, better to change the filter element.

• If the filter element is made of foamed plastic, it should be put in kerosene or incombustible detergent for cleaning, then dryed, and coated with a small amount of lubricating oil. Please note that don’t put too much, otherwise it will reduce the air input. And finally put the element inside the cleaner.

• Confirm that there is nothing wrong with the air cleaner. Then check the 50cc carburetor. For plunger type carburetor, use compressed air to blow throuhg all the holes and tube so as to check if the position of the main oil needle is right or not.

• For those motorcyle with vacuum diaphragm type carburetor, you need to check start heating automatic valve. Firstly, put the yellow wires of start heating valve to anode of the battery and green wire to cathode of the battery. Then, about five minutes later, connect polyethylene pipe to fuel incremental loop and blow it with your mouth, if the loop is full closed, there will be no ventilation; If it can easily ventilated, which indicate the automatic valve can’t close the loop, then you need to change the start heating automatic valve.

The blue exhaustBlue is a color of melancholy. If the exhaust is blue, you won’t be happy too, which indicates that the engine oil is burning. This is mainly caused by the following reasons:

• There is a large clearance between cylinder and piston or valve and valve guide, so there is more engine oil inside the cylinder. This kind of situation mostly happened on those motorcycle used for long year. So you need to check the clearance of the two places regularly, so as to prevent excessive wearout.

• When checking the clearance between piston and cylinder, you need to pay more attention to the wearout of piston and piston ring. You need to measure the diameter of the piston skirt and change piston when it come to wear limit. And you also need to check and measure the clearance between the piston ring, elasticity and light leakage, and change the ring when it is worn, damaged or reach the limit.

• Check the clearance between the valves and valve guide, you need to pay more attention to the wearout of valve stem outside diameter and valve guide inside diameter. Use the outside micrometer to measure diameter of the valve stem when repairing, if it reaches the limit, you need to change the valve. Before measuring valve guide, the carbon deposit should be removed by reamer. The reamer should rotate toward the right when taking it into or out of the valve guide, otherwise, it will damage the inner of the guide. Use the boredial indicator to measure inside diameter of the valve guide, it is greater than the limit, then you need to change the valve guide.

The direct cause of blue exhaust is the large clearance between cheap brakes or valve and valve guide, which is due to exceed wear of these parts. So choosing the appropriate lubricant to prevent the excessive wear of engine is an important way to avoid the blue exhaust. Be sure to use qualified lubricating oil at ordinary times, you can choose it according to operating manual of your motorcycle.The white exhaustWhite symbolizes purity, almost everyone can accept it. But when the exhaust is thick white like milk, you should pay more attention of it.Exhaust in thick white means there is too much water inside the exhaust. There are mainly two reasons:

• You have been fooled by gas station, there is too much water inside the gasoline.

• Or the problem is on your motorcycle itself. The channel gasket or cylinder liner is damaged so that the cooling water come into the cylinder.

Then there is too much water inside the gasoline, in addition of the white exhaust, it will also cause exhaust pipe blasting or carburetor failure, which will harm the motorcycle sprocket.You need to remove the gasoline which contain water in gasoline tank or gasoline channel in time. Besides, if the channel gasket is damaged, you need to change it promptly. And if the cylinder liner is damaged, you need to find someone professional to repair it or even change it.