JH600 Valve Problem

[milton]

Just got my JH600 back from Dr. Cui’s last night after leaving it at his shop for 4 days. The problem I had was excessive engine stalling. The problem is not new, but it had just gotten so severe that it stalled at every traffic light.

Prior to sending it to Dr. Cui, a few of us JH600 owners have been systematically swapping out original Jialing parts with genuine Bosch parts. This is partly due to my wishful thinking of doing anything to avoid a major open heart surgery on my bike. Although Jialing adopted Bosch fuel injection and the ECU hardware for our JH600, it cheaped out on all the supporting sensors and the crucial software for the ECU. All Jialing parts surrounding the ECU have genuine Bosch counterparts available, with hopefully better quality. Genuine Bosch parts are not all that expensive, so we have been replacing a few of those parts at the slightest doubt that they may be the fault for anything. So far we have replaced the following:
CPS (Crankshaft Position Sensor) 曲轴位置传感器 ¥130
FPR (Fuel Pump Relay) 油泵继电器 ¥30
TPS (Throttle Position Sensor) 节气门位置传感器 ¥65

I’d say the TPS swap-out is money well spent. My bike is a lot more responsive with Bosch TPS. However, that wholesale swapping effort did not fix the stalling problem. Dr. Cui was suspecting the camshaft valve is at fault all along, for which Motokai sent his in to Dr. Cui’s originally. Hence the sending of my bike to his shop for open heart surgery.

I did not attend the operation (for lack of time and also faint of heart :-)), but the result was quite positive. The excessive stalling is gone and my bike runs better than ever. I am not sure what he had done to my bike. I was told that the camshaft valve needed “adjustment”, with some spring replaced and some part of it also replaced by something he “found” (and subsequently machined to fit). I don’t have any detail and pictures to show, but the outcome is indeed impressive. (Motokai: There is no adjustment made to the idling speed)

BTW, do make sure to change the motor oil and flush the coolant after such a major heart surgery at a Chinese workshop. After the service you can just assume you had a refill of dirty oil and 100% Huangpujiang （黄浦江）water in your cooling system.

Now finally I am ready to go on my 10-day trip planned for next week.