CB1100 Idle speed instability problem

[Houtman_imp]

I sincerely hope that after all the hard work you did that your bike runs perfectly from now on till the end of time.
Also thank you for keeping us updated and informed about the rebuild.

[the Ferret]

Update: Buttoned the bike up tonight. Said a prayer, turned the key on and hit the button, and it started immediately! Initial idle speed was approx. 1250 RPM. Put 22 miles on the bike, mostly around town, but included a short (about 5 mile) stretch of freeway. The idle speed very quickly dropped to about 1,050 RPM, where it remained the rest of my ride. So it initially appears that the new IACV solved the high/low/stalling problem, as the bike ran perfectly, but it's too early to reach that conclusion. I need to put several hundred miles on the bike before I believe that it is fixed. I'll post some more information soon, including some pictures. Thanks to all the great forum members for their technical support and encouragement.

Awesome Dave, fingers crossed that through your diligence and hard work, that your bike is now among the normal. You certainly deserve that.

[dave]

Thanks guys, you're all the best! I have a bunch of pictures I need to upload from my phone that I will be sharing. I would like to put them into PowerPoint slides so I can edit them with comments- can I upload PP pictures to this site?

[SportsterDoc]

Update: Buttoned the bike up tonight. Said a prayer, turned the key on and hit the button, and it started immediately! Initial idle speed was approx. 1250 RPM. Put 22 miles on the bike, mostly around town, but included a short (about 5 mile) stretch of freeway. The idle speed very quickly dropped to about 1,050 RPM, where it remained the rest of my ride. So it initially appears that the new IACV solved the high/low/stalling problem, as the bike ran perfectly, but it's too early to reach that conclusion. I need to put several hundred miles on the bike before I believe that it is fixed. I'll post some more information soon, including some pictures. Thanks to all the great forum members for their technical support and encouragement.

I'd suggest that a spirited long ride should be considered part of the repair process! Congratulations on all that you accomplished.

[Magnus_imp]

Good to hear, Dave! What part of San Diego are you in?

[Cormanus]

Thanks guys, you're all the best! I have a bunch of pictures I need to upload from my phone that I will be sharing. I would like to put them into PowerPoint slides so I can edit them with comments- can I upload PP pictures to this site?

Dave, I’m sure we can figure a way to do this. Let me know if you have any trouble.

[dave]

Good to hear, Dave! What part of San Diego are you in?

Hi Magnus. I am just off the Genesee Avenue exit from 163, near the intersection of Linda Vista Road and Genesee Ave. And you?

[dave]

Update, and something interesting: I've had the bike out the past two evenings (25 miles Wednesday, a lot of stop and go) and about 10 miles last night. So far it is running perfectly!

To my surprise, for the very first time, (at least that I have ever noticed) I discovered that my idle speed increased a very small amount when I was releasing the clutch when the engine was just started and still in the cold/high idle mode. I had to actually stop the bike twice to determine if what I was seeing was real, or imagined. Just at the point where the clutch would begin to engage the RPM increased by less than 200 RPM. I have never noticed this before, but the increase was so slight that it's possible that I just missed it. This is a topic that was brought up (I believe in this thread) a while back, but not much was ever said about it (Ferret commented about it). Ever since the topic first came up I was checking my bike to see if it was happening, and it was not. But like I said, it was such a small change in RPM, and it happened so quickly and almost completely unnoticed, it may have been happening to my bike and I never noticed. Has anybody else noticed that their bike does this also? I wonder if replacing the IACV had anything to do with this?

[the Ferret]

Dave that only happened to my bike once, when it was cold out (around freezing iirc.) I have not been able to repeat that in the 2 times I have tried since it has warmed up. Since then, the rpms have always gone down when letting out the clutch in gear with the idle on cold idle and hand off the throttle. I thought it had to do with further enriching the circuit due to cold outside air temp, but I would think that would not be an issue in San Diego.

BTW that is something I would have never even thought to try had someone not mentioned it here.

[pdedse]

Update, and something interesting: I've had the bike out the past two evenings (25 miles Wednesday, a lot of stop and go) and about 10 miles last night. So far it is running perfectly!

To my surprise, for the very first time, (at least that I have ever noticed) I discovered that my idle speed increased a very small amount when I was releasing the clutch when the engine was just started and still in the cold/high idle mode. I had to actually stop the bike twice to determine if what I was seeing was real, or imagined. Just at the point where the clutch would begin to engage the RPM increased by less than 200 RPM. I have never noticed this before, but the increase was so slight that it's possible that I just missed it. This is a topic that was brought up (I believe in this thread) a while back, but not much was ever said about it (Ferret commented about it). Ever since the topic first came up I was checking my bike to see if it was happening, and it was not. But like I said, it was such a small change in RPM, and it happened so quickly and almost completely unnoticed, it may have been happening to my bike and I never noticed. Has anybody else noticed that their bike does this also? I wonder if replacing the IACV had anything to do with this?

Good to hear...so far, so good; fingers still crossed for you.