Under general temperature conditions (above -5 ° C), when the motorcycle engine can not start normally after 1 to 3 starts, it indicates that there is a fault. The failure is nothing more than two aspects, that is, the so-called oil circuit or circuit (this does not discuss the crankcase, cylinder leakage and insufficient pressure, piston ring wear and fracture and other reasons). Oil circuit faults are easy to find, as long as the oil circuit system is not blocked, the carburetor is working normally, there is fuel and the quality meets the requirements, it can be considered that the oil circuit is basically troublefree. The circuit fault is more difficult to find, and the engine can not start immediately is mostly caused by the electric fire circuit fault. The following describes the steps and methods to quickly and accurately find the fault point of the circuit.

First unscrew the spark plug, let the hex nut of the spark plug close to about 5 to 8 mm from the cylinder block, and let the spark plug dress is facing our line of sight, that is, our eyes can see the space inside the spark plug center electrode.

Start the engine several times at this time, there can be the following four situations:

1. A 5-8 mm long spark is generated between the spark plug and the cylinder block, and the discharge sound can be heard. At the same time, the spark is generated in the gap of 0.7 mm between the center electrode and the side electrode of the spark plug. This situation shows that the high voltage ignition circuit is normal. If the engine still cannot start, check whether the ignition advance Angle is correct. If the ignition advance Angle is correct, it indicates that the high-voltage ignition system has no fault, that is, the circuit part has no fault. Then the reason why the engine does not start should be considered from the oil circuit or other parts.

2. There are 5~8 mm sparks between the spark plug and the cylinder, but there is no spark between the central electrode and the side electrode of the spark plug, and there is a spark in the internal space of the central electrode. This situation indicates that the high-voltage ignition circuit is still normal, but the carbon accumulation inside the spark plug is serious or the spark plug insulator is broken down. A new spark plug will start the engine.

3. The length of the spark generated between the spark plug and the cylinder is less than 5 to 8 mm, only 2 to 3 mm. At this time, first check the gap of the platinum contact of the breaker, if it is between 0.25 and 0.5 mm, it should be considered normal (generally adjusted according to the provisions of the manufacturer's product manual). Then polish the contact with a fine emery cloth for dozens of times, and then wipe the contact surface with a clean rag dipped in gasoline.

Then start the engine several times, while starting carefully observe the size of the spark between the contacts of the breaker. If the spark is large, the capacitor in parallel with the contact has failed (open circuit). Replace the new capacitor can start; If the spark is small, it indicates that the high-voltage coil or high-voltage lead wire is broken down. At this time, it is advisable to lower the magneto high voltage takeout line, let the head of the screwdriver from the coil high voltage extraction end 5-8 mm, the naked part contact the conductive part of the car body, and then start the engine once. If a spark is generated between the screwdriver and the high voltage lead end of the coil, and a discharge sound is heard, it indicates that the high voltage coil is good, but the high voltage lead line is broken down. Replace a good high-voltage cable and the motorcycle can start immediately. If the high voltage coil is broken down, it must be replaced in time.

4. There is no spark between the spark plug and the cylinder block. In this case, it is necessary to see whether there is a spark between the contacts of the breaker when starting. If there is a spark, it can be handled according to the third case. If there is no spark, it indicates that there is a fault in the primary (low-voltage part of the ignition circuit).

(1) First check whether there is a gap between the breaker contacts. If there is no gap, adjust the contact gap to 0. 25 to 0. 5 mm, and hit the friction clean. If it cannot be adjusted, it may be that the friction block of the breaker is worn, broken, fallen off, or the pressure spring is broken and failed, and it should be removed and replaced with a new one.

(2) If there is a gap, the surface of the contact should be polished clean.

(3) If the engine still can not start, it is necessary to check whether the lead wire of the low-voltage circuit is worn and contacts the car body to cause short circuit, or there is a welding, broken line. If there is a place to connect the iron, use tape or other methods to make it out of contact. Where there is a break, we need to rewire and weld it. If there is no such phenomenon, it is necessary to check whether the capacitor short-circuit failure. The capacitor can be welded down by other methods (such as the method of connecting the lamp with a battery) to measure whether the low-voltage coil is broken or there is an open welding place. Where there is welding, it should be welded securely in time. If there is a break fault, it should be removed and rewound.

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