CB1100 Idle speed instability problem

[dave]

Hi all, it's been a while since I've posted to this thread, but here's my latest update: Right now it's a guessing game whenever I ride my bike - will it idle high (1,500 RPM), will it idle low, and possibly stall (500 - 600 RPM), or will it run perfectly? Honestly, it's been alternating between all three conditions. My low idle has been acting exactly the way others have described theirs; dropping to about 500 RPM and then slowly returning to 1,000 RPM, if it doesn't stall. For those who are experiencing the low RPM idle: When this condition occurs, can you please see if you can sense any difference in the way the engine responds when blipping the throttle lightly, from idle speed, like when you are down shifting? I sense that my bike does not respond "normally" when blipping the throttle when it goes into the low RPM mode, and If I was to guess, I would say that the mixture is too lean. Could this be an indication that the IACV is leaning the mixture out too much? I don't know, but I really think that the IACV is a big part of our problem, I am just not convinced that it is the root cause because one of the guys posted that he replaced his IACV and the problem was not cured. Also, I don't understand how unplugging my EOT gauge eliminates the high idle problem (I never unplugged the EOT sensor when I had a low RPM condition). Hopefully one of us will get to the root cause of this. I understand Honda changed the part number of the IACV. Is anyone brave enough to try the new, 2017 American part number IACV in their older model?