Some of the motorcycle owners always ignore small parts when doing the maintenance for their motorcycle accessories, and then it will leave some problems or quality issues for the motorcycle even after repaired and affect the service life.

Here we will discuss about some problem which is easy to be ignored in the process of motorcycle maintenance, like circuit, oil, gas or mechanical parts.

ignitionMinimum ignition speed

In general, magneto ignition system has minimum ignition speed and it can ensure that the ignition system can realize high voltage ignition at low engine speed. However, most repairman will usually remove the spark plug on the fault engine and do the arcing tests on high-pressure damping cap when there is a ignition failure. These methods are simple and easy and have been widely adopted by them. But some engine failure like difficult to start, is due to ignition coil and the electronic igniter with a high ignition speed.

Such as Honda CH125 water-cooled scooter, its minimum ignition speed is 300 r/min. If the minimum ignition performance reduces, the minimum ignition speed increase, and it sometimes even need to reach more than 400 r/min to ignite. If the repairman still use simple arcing tests as above, then they may be fooled by some false appearance and even mislead. This is because there is no compression resistance in the cylinder when the piston runs up and down without spark plug in the engine; the start speed is above 400 r/min, which is much higher than with speed with the spark plug. At surface, the spark plug does have a spark at this moment, but after putting it on engine and then apply electric start or pedal starts, then, there is certain pressure inside the cylinder and the running resistance will increase, start speed will be only about 300 r/min. If the battery voltage is low, then the start speed is even lower, which can’t meet the minimum ignition speed, of course, the motorcycle will not start.

Therefore, when using the spark plug or ignition coil to ignite, make sure to install a spark plug in the engine, or it is even better to use electronic tachometer to measure start speed. If using the old battery around 12 V, the start speed is around 300 r/min to 350 r/min, the spark is weak, while using the new battery above 13.5 V, the start speed is more than 400 r/min, the spark is blue and white, then we can get a preliminary conclusion: the minimum ignition speed is too high. Then, you need to test the performance of each electric equipment of ignition system, and replace the ignition coil and electronic igniter for contrast test, which can eliminate the failure.