If the fuel pressure is too low, determine whether the fault is caused by the pressure regulator or the fuel pump in the fuel tank. Because the pressure regulator is easy to check, first remove the relevant vehicle appearance cover, connect the oil pressure gauge in the fuel line in series, hold the appropriate size of pliers to clamp the pressure regulator rubber oil return hose, at the same time open the main ignition switch, so that the fuel pump into work. If the oil pressure from the oil pipe is higher than that before the pliers clamp the rubber oil return hose, it can be judged that the pressure of the fuel system is low. The reasons for the low oil pressure are as follows:

(1) fuel pump. Because of motor speed is too low, fuel pressure in the fuel line to reach 200 ~ 250 kpa (different models, different rules of oil pressure), or the fuel filter mesh blocked by foreign body, don't come on fuel pressure, need to check the fuel pump performance (including check whether the battery voltage is above 11 v), fuel filter, filter and fuel transfer lines, depending on the situation to repair or replacement.

(2) oil pressure regulator. The general reason is that there is a foreign body stuck between the ball valve and the seat in the regulator, so that the oil pressure is low, it is necessary to carefully check the oil pressure regulator (see the figure below) performance, fuel line, etc.

(3) fuel injectors. The coil of the injector dc impedance value is abnormal, resulting in its not working. It can be confirmed by testing its electrical parameters (please refer to the values specified in the service manual for each model);

The nozzle hole of the injector is blocked. Because the nozzle is always working under high temperature and high pressure environment, the quality requirements of the fuel are quite high, if the user greedy for cheap and add inferior fuel, it will produce sediment in the combustion process.

The sediment will block the needle valve and valve hole of the oil injection nozzle, affect the performance of the precision parts of the electronic injection system, and reduce the power performance. Sediment will form carbon deposition at the intake valve, resulting in a loose shutdown, resulting in motorcycle difficult to start, engine idle speed instability, increased fuel consumption accompanied by excessive exhaust emissions, will also shorten the service life of the three-way catalytic converter.

In this regard, can be removed for careful cleaning, to eliminate the blocking phenomenon. If the blockage is too severe to clean, only replace the injector with a new one.