CB1100 Idle speed instability problem

[dave]

Hi Dave, good to hear from you again.

A question; in general would you agree that the issue starts gradually at some point and then gets progressively worse?

Not trying to put words in your mouth , just thinking in one direction and one step at a time if that makes sense..

Cheers max

Hi Max. My issue started with the slow idle / stalling. However, it was never a bad as the video on this thread. I could always restart my bike after it stalled, and it would run fine at a higher RPM - it just didn't want to idle. This issue went away by itself, and then the high idle (1,500 rpm) started about two months later. This lasted about 1 - 2 months. After a WFO run in the desert (started at low RPM in 4th gear to make a pass with a passenger on back and ran through the gears while wide open, but never exceeding 6,000 RPM), the high RPM idle issue cured itself also, and has never returned. About 2,000 trouble-free miles later the low idle / stalling has returned. I can keep the bike from stalling by blipping the throttle - it runs fine as soon as the RPM is increased above about 3,000. This low RPM / stalling comes and goes at will now. I will put my bike away when the problem occurs, and start it up the next day and it will run perfectly. I believed that the high RPM issue was brought on by slow, stop & go riding, when the engine got hot. But I have seen no connection to the riding conditions or temperature for the low RPM / stalling. In my opinion, the fuel mixture is leaning out when the low RPM condition occurs. I can sense a different response when I blip the throttle when this condition is happening that sure reminds me of a cold starting condition with a carbureted bike. Do you think there is any connection to the level of oil in the bike and this problem? Is it possible that excess oil somehow causes the EOT sensor to send a bad signal to the ECM? Also, my bike experienced poor low speed running from the day I bought it, which was finally cured by the TPS reset (I am extremely sensitive to how my bike runs, and the dealer said it was running fine, but I felt an immediate improvement after the TPS reset.) My bike has never shown an error code. Thank you so much for digging into this - I just don't have the time, or experience to diagnose electrical problems on my own.