JH600 stalling

[998S]

First I should say that I am not at all experienced with JH-600's (the closest I have been to one was from the other side of the showroom window)..
But I have a lot of wrenching experience on many bikes, including 1, 2, 4 and even the beautifully Benelli-Sei 6 cylinder.
I do all maintenance by myself, including on my Ducati's for the street and the track.

The reason this thread got my interest is that Ducati's have exact the same problem.
The modern series like the 848 and 1098 have persistent stalling issues, on idle, but mostly on slowing down and shifting back.
Sounds familiar, right?

It is correct that 1 & 2 cylinders are more vurnarable for this then e.g. 4 cylinders (specially if they have relative light flywheels - not enough "swinging" weight to keep the engine turning), but it no excuse, and does not need to happen!

In the Ducati case, the stalling is mainly caused by the injection settings, which, due to the stringent pollution regulations of today, are set too lean (simply said; not enough fuel sprayed in the mixture).
If you ride, and reduce speed to a stop, the air mixture sensor measures the lack of "load", and reduces the fuel even more.
By the time you come to a stop, the mixture is simply not enough to turn the engine around, stalling as a result.

The second reason that I think it might be related to a lean mixture, is that I read that someone noticed the very high temperatures on the exhaust.
Although exhausts can be red hot (let a bike run idle for a while at night, and look the headers...), a lean mixture is always hotter, because fuel cools down.

The third reason I think it might be fuel related is that someone else noticed it is getting worse with a more open exhaust.
Same story, an open exhaust leans out the mixture due to less resistance, and therefore an other pulse frequency in the exhaust (simply said, the gasses can escape faster, sucking out more air through the cylinder, which results into a leaner mixture as the fuel-amount does not change. That is also causing the popping on deceleration..).

Although I guess that the fuel setting is probably not the only reason for the stalling issue, I highly wonder if replacing half of the engine is necessary.
Frankly that sounds very much as a TIC solution, not knowing the problem, and just starting to change parts, hoping sooner or later the problem will be fixed.
I suspect that the JH-manufacturer got it wrong on the exhaust gas regulations it has to fulfill for the Chinese approval, then set the injection too lean.

Did anyone ever measure the CO level on the exhaust at idle speed?
It should be interesting to see that value as a starter.

Eric

PS. An idle speed of 1700 is FAR to high for a 2 cylinder.
Even a high compression Ducati 2 cylinder runs perfectly at 1100-1200 rpm idle, and my Chang Jiang with a large flywheel ticks over at 800 rpm ....