CB1100 Idle speed instability problem

[Cbman_imp]

Well well well; hello everyone! I have good news (at least in my case). Like many others, I was having idle problems and bike shutting off when stopped at a light or while riding. After reading all the discussions here, I decided to change the iacv myself without ant troubleshooting(I know its crazy but didnt want yo spend hours troubleshooting). So I boight the part and with the help Ingot my hands on a service manual. So I took apart the seat, tank, left and right covers; the rear air filter housing and for the life of me, I couldnot remove front air filter housing that is attached to throttle control. In the effort to do all these, I had disconnected the battery and most harnesses including the computer. So I decided to put everything back and accept defete and take the bike to a shop for repairs. I put everything back and to my surprise the bike was fixed by just disconnecting all the parts and letting it sit for a few days... guys; if you have the same issue; try this; it may help!

[Nachodaddy]

Well well well; hello everyone! I have good news (at least in my case). Like many others, I was having idle problems and bike shutting off when stopped at a light or while riding. After reading all the discussions here, I decided to change the iacv myself without ant troubleshooting(I know its crazy but didnt want yo spend hours troubleshooting). So I boight the part and with the help Ingot my hands on a service manual. So I took apart the seat, tank, left and right covers; the rear air filter housing and for the life of me, I couldnot remove front air filter housing that is attached to throttle control. In the effort to do all these, I had disconnected the battery and most harnesses including the computer. So I decided to put everything back and accept defete and take the bike to a shop for repairs. I put everything back and to my surprise the bike was fixed by just disconnecting all the parts and letting it sit for a few days... guys; if you have the same issue; try this; it may help!

Cbman, the IACV is not the problem. It is a lot easier to install a new ECU and solve the problem once and forever. My 2013 ran okay for a week or so after I got the new IACV, but then the problem returned. Only when I put in the new ECU did it idle like a new bike. I hope your problem is resolved, but, if it returns, get a new ECU. The intake air control valve (IACV) probably is not your problem. Good luck with this.

[dave]

I am amazed that after over eleven years, and dozens of owners experiencing this exact same problem, that Honda hasn't figured out the root cause. I replaced my IACV eight years ago and never experienced the problem again. However, there are forum members who have replaced their IACV and this did not solve the problem for them. Some forum members report that ECU replacement is the only solution, and some forum members from Europe have reported that an ECU reflash cured the problem for them. Honda America will not reflash an ECU. The fact that Honda doesn't even acknowledge the problem doesn't speak well for them.
Cbman. Report back to us in a month and tell us if your idle issue has been permanently fixed. My bet is it isn't, but good luck.

[Nachodaddy]

It is worth mentioning that the ECU I bought from Partzilla had a different part number. No one listed the ECU with the original part number for the 2013. Problem is that wasn't the only year with the problem, so I don't know what happened. I know one of our members in South Korea took his to his Honda shop and they solved his fast idle problem by replacing the ECU. That is why I replaced my ECU.

[Cormanus]

From the 'Old' Forum yesterday:

Hi guys,I live in Europe, my CB1100 is a 2013 model with ABS. After suffered the problems related to the idle instability, today my bike has been updated with the last version of the ECU software, ECUID 0101390102. I hope this can help you.