market dynamics
What should the motorcycle do when it turns off in the middle?
Release date:2021.06.03

Recently to repair a haojew HJ125 type riding motorcycle, according to the owner, he this motorcycle on the way, feel the engine suddenly do not add oil, then the engine suddenly flameout, start the engine again, this car is no longer hair

After receiving the vehicle, open the ignition key, press the start button, and conduct the engine start test. After electric startup is pressed, the starter does not work. As the car engine has no foot start, we have to use the method of connecting the working circuit of the starter directly to test the starter.

Use a screwdriver to short connect the battery fire line terminal on the starting relay and the fire line terminal of the starting machine. The starting machine quickly reacted and forcefully drag the engine to reach the starting speed and enter the starting working condition. But unexpectedly, the engine just can't start and catch fire.

Unplug the high voltage wire from the spark plug, hold the high voltage wire against the engine cylinder block and keep a distance of about 6 mm, carry out the high pressure fire jump test, and connect the starter circuit directly again to start the engine. Under normal circumstances, there should be bright electric spark between high voltage line and cylinder block right now. But it turned out to be disappointing. There was no spark, and by this time it was clear that something was wrong with the ignition system, which caused the engine to stall and the car to fail to start.


The ignition system of this motorcycle is in DC ignition mode. A multimeter is used to detect the working voltage of the igniter's working power conductor to the ground. The test result shows that the working power voltage of the igniter is zero, indicating that there is something wrong with the working power voltage of the igniter.

According to the working principle of the ignition system, the emergency flameout switch controls the ignition system's working power supply and the starting button's working power supply on and off. From the analysis of the fault phenomenon that the electric starting device can't work and the ignition system can't work, the emergency flameout switch has a fault.

Open the right hand handle and use the multimeter DC voltage to detect the welding points of the two wire ends of the emergency extinguishing switch. The emergency extinguishing switch is in the open position. The contact point of one wire end has +12V DC voltage to the ground, and the DC voltage of the other wire end contact is zero. The test results show that the emergency flameout switch has a bad contact fault.

Repair the emergency flutter switch so that it can work normally, press the start button, the start machine can be put into work. The multimeter was used to test the igniter's working power supply voltage. The working power supply voltage of the igniter was +12.3V. The test results showed that the emergency extinguishing switch had bad contact with the fault.

Connect the disconnected wire end, press the starting button, so that the engine into the starting condition, holding the high voltage line against the engine body and maintain a distance of about 6 mm, high pressure jump fire test, the high voltage line on the engine body produced a strong high pressure ignition spark, the test results show that the ignition system troubleshooting.

Install the high-voltage line, start the engine for inspection, the engine enters the starting condition, the engine can not start fire after several consecutive starts, the analysis reason may be that the engine is started for a long time, resulting in the combustion mixture in the engine cylinder is too thick, so that the conventional operation can not start the engine. It is usually called "flooded tank".

Turn the throttle handle to the maximum opening of the carburetor throttle to increase air intake and dilute the excessive combustible mixture. Press the starting button, the engine enters the starting condition, the engine first has the desired phenomenon, and then starts the ignition engine to run normally.

After inspection and confirmation, the engine can not start the ignition fault has been eliminated, the reason is that the flameout switch has bad contact.