CB1100 Idle speed instability problem

[Nachodaddy]

Spent the afternoon reading through this long thread and found that it occurred on a few 2013s over the years. While it looks like a replacement of the IACV is the cure, I want to see how the bike responds to a few things first. I will keep you posted. I won't be doing anything drastic for awhile.

[Cormanus]

Apologies Nachodaddy. Yet again my memory is failing me. It will be good to hear what you come up with.

[pdedse]

Here we go again.
I bought my 2013 standard in August, 2021 with around 4500 miles on it. A very clean bike that looked well cared for. I don't ride much, but recently the idle will suddenly drop to around 500 RPM and the engine will die. This first happened when I was riding very slowly, using the clutch to regulate my speed while practicing very slow speed turns, figure-eights and U-turns in an empty parking lot. Then it happened after riding fairly fast and stopping at a traffic light. Clutch pulled in, bike in 1st gear, engine idles down to 500 for a second or so and dies. This happened a few more times on the way home. The bike is hard to start when this happens. Enough so, that other traffic is getting irritated with me and I have no place to move the bike, but have to keep trying.
I will take it out and see if a few things help, like putting it in neutral and leaving the clutch out when I start it, turning off and on the master switch before starting it after it dies, and rotating the throttle completely each time.
I think it is too old for Honda to give me any kind of warranty coverage and I have absolutely no confidence in any of the local "Honda" shops.
Weather at this time is very mild - sixties to mid-seventies (F) dry air, typical desert winter weather. I very much appreciate all the posts, attachments and pictures others have posted of their experiences with this problem. If I had been smart enough to read this forum before buying this bike, I would not have bought it, especially at the price I paid.

Sorry for your idle troubles. When my '14 standard started acting up, it was about 6 months out of warranty. I thought Honda might step up to help with the issue and wrote them a letter explaining everything, and the fact that some 25 other owners had experienced this on this site, and asked them to please consider extending warranty. Customer Service called me a few weeks later and asked questions, was sorry to hear of the difficulty...but bottom line was--you have to take it to dealer and let them diagnose the issue, and after that Honda would take it into consideration. Dealer said it could be hard to diagnose because the issue was intermittent, and if time were spent trying to make the problem happen, that would be time charged at $125 per hour. Sevice manager said he had seen cases where he thought Honda should cover things, but didn't and sometimes the reverse--he simply had no way of knowing what they would do. In the end, leery of a long drawn out ordeal, I decided not to go that route and simply traded it in on a new bike. But at the time 2016-17, not as much was known about the likely culprit...the IACV.

[Enzofour_imp]

I speak from direct experience, do not waste time with useless attempts, replace the IACV and solve the problem forever.
Enzofour

[Nachodaddy]

Apologies Nachodaddy. Yet again my memory is failing me. It will be good to hear what you come up with.

No worries, my friend. If only I could replace my memory as easily as replacing the IACV.

I speak from direct experience, do not waste time with useless attempts, replace the IACV and solve the problem forever.
Enzofour

Enzo, I am encouraged by your replacement of the IACV without removing so much from the bike. It would be helpful if you could list where you started and how much you removed and what problems you found and how you over-came them on the way. Thank you for your encouragement.

[1973cb750]

Today the Honda dealer informed me that in 2016 Honda sent dealers an ECU update.
This update was not an official reminder, but a tip to use on 2014/2015 models with low idle and shutdown issues.
On 14/04/2021 they will install this update for me, we will see the effects.
I will try to get the name / code of the firmware for this update.
Meanwhile, with the replacement of the IACV the bike didn't give me any more problems.

i wonder if the usa will get this? mine has zero issues '14

[Enzofour_imp]

[/quote]
Enzo, I am encouraged by your replacement of the IACV without removing so much from the bike. It would be helpful if you could list where you started and how much you removed and what problems you found and how you over-came them on the way. Thank you for your encouragement.
[/quote]


First you need to get a long and flexible Phillips screwdriver, otherwise you will not be able to unscrew the central screws of the airbox box (see arrows).
With a lot of patience you have to free the airbox of all the cables it supports and all the various pipes connected to it, I recommend you take many photos before disassembling the various pieces, so you can put everything back as before.
You will also need to unclip some electrical connectors to make room for yourself.
Now loosen the sealing ring between the airbox and the airbox (long screwdriver),
Here you have to use the flexible screwdriver to be able to unscrew the central screws that separate the airbox cover from the plate that contains the flutes of the throttle bodies. ATTENTION! the box comes out from the right, but the space is insufficient so you have to heat the box with the hair dryer or heat gun, in order to make it elastic and withstand the effort, same thing when you reassemble it. ATTENTION! in the upper internal part you will see a joint, when reassembling it you must match it in the right way (take pictures first).
Now you can replace the evil IACV.
Do everything calmly and before starting and while you take apart the parts, take your time to look and evaluate how best to do it, I watched it for 1/2 day before starting.
Good job.

[Nachodaddy]

Thank you Enzo, this is very thorough and helpful.

[Houtman_imp]

I never had an instability problem on any of my CB 1100's but that is a very good post from Enzo !

[max]

That's incredibly helpful Enzo, i'm sure a lot of people will be grateful for your input, very skilled and dedicated work ( and i like the clock.....) my kinda guy as you sit down with some coffee and nut it out in your head .

Maybe it is clear what to heat at the airbox to be able to pass it through the frame but if you can elaborate which part you heated up that would be even better for the future ( and do you rotate the airbox? ), i like to be as complete as possible to facilitate the next guy.

And Nacho; mark the new iacv before swapping it out somehow ( you know ? )

What was the NEW partnumber for the iacv anyone ?

Moderators would it be possible to copy Enzo's post to the how-to section so it does not get buried in the thread?

Also copied the entire post to my harddrive and baptized it " THE ENZO METHOD "