CB1100 Idle speed instability problem

[dave]

So, I'm not the only one who experienced an improvement after the WFO ride! Here's an update, and also some more information to ponder: I've put about 600 miles on my bike since the WFO ride I described that (coincidentally?) cured my fast idle / slow idle / stalling. The bike has for the most part been running better than new, except for one extended slow speed, stop and go ride where the idle would momentarily drop to 750 RPM (it used to drop to 500 RPM and sometimes stall) and then return to normal (1,050 RPM) - this happened three times. If you're experiencing the idle problems, please comment on the following: johnf514 uploaded a video (at my request) of the sound his fuel pump and IACV make as you turn the ignition on. John had his IACV replaced by the dealer, and it cured his idle problem. Listen to John's video and you can hear the IACV cycling rather loudly (the fuel pump has it's own sound). When my bike experiences the idle problems I can barely hear the sound of the IACV cycling when I turn on the ignition. When my bike is running good (no idle problems), the sound of the IACV cycling when you turn on the key is MUCH louder, and sounds exactly like the video johnf514 recorded. Please listen to John's video (it can be found somewhere in this thread), and then listen to the sounds your bike makes - do they sound the same? Something tells me that when you can barely hear the sound of the IACV cycling when you turn the key on then you're going to experience the idle problems. So the question is this: Is the problem with the IACV, or with the software or sensor that gives the signal to the IACV?