CB1100 Idle speed instability problem

[dave]

I am not questioning that the IACV was sticking, and lubricating it cured the problem. I just want to share what I observed when I replaced my IACV: The original (defective) IACV did not show any signs of sticking in the aluminum throttle body assembly. There were no signs of galling, or abrasion, and there were no signs of any dirt or anything else that could have caused the IACV to stick. I performed side-by-side tests activating and deactivating the old and new IACVs side-by-side, and they both functioned identically. My conclusion is that the defective IACV that I replaced had an internal, intermittent short that came and went randomly. I applied a very light coat of grease to the new IACV and have never experienced the problem again. I would NEVER go through all the work to remove an IACV just to lubricate it and reinstall it if there was no hard evidence that it was sticking - once you have the old one out just replace it with a new one, unless you have nothing better to do with an entire day.

[max]

Just had an idea Dave, do you think it is possible that the brass center part of the piston is sintered?
Sintered bronze is porous, is used as bearings for starter motors and the pores can/should be filled with lubricant, what if some were not filled and made it off the assembly line and got used on some of the 2014 models?

[dave]

Just had an idea Dave, do you think it is possible that the brass center part of the piston is sintered?
Sintered bronze is porous, is used as bearings for starter motors and the pores can/should be filled with lubricant, what if some were not filled and made it off the assembly line and got used on some of the 2014 models?

Hi Max. I saved my old IACV and just looked at it; the moving piston does not appear to be sintered. It has a very smooth surface, possibly polished. It doesn't look like it is brass, and I don't think it is chrome plated; it is non-magnetic. I would guess aluminum, but I think an aluminum surface would oxidize and not maintain this shine. It sure looks like steel, maybe stainless? What's your guess? I posted a picture of it somewhere in this post a couple of years ago and the color in that picture does give the impression that it is brass, but the picture is misleading.

[max]

Thanks for that info Dave, i was just brainstorming to see what the germans have done to repair their bikes.
Agree with the previous member who suggested to replace rather than clean the iacv after all the work to get it out, but just curious, cheers.

[Enzofour_imp]

Is it necessary to remap the ECU when replacing the IACV?

[Lord Popgun]

No. Replace it and it’s done.

[Enzofour_imp]

Eureka! IACV removed by removing only the airbox,









now I await the new IACV

[peterbaron]

Good job, Enzo

[pdedse]

Eureka! IACV removed by removing only the airbox,









now I await the new IACV

Seems like such harmless little thing. Good luck with install on the new one when you get it.

[GoldOxide_imp]

Eureka! IACV removed by removing only the airbox,









now I await the new IACV

Seems like such harmless little thing. Good luck with install on the new one when you get it.

Harmless? Looks like it should go into some orfice somewhere.

Nevertheless, I hope it just works for you.