CB1100 Idle speed instability problem

[dsan1964_imp]

My bike has been on a high idling kick. Right about 1400. A little irritating


Sent from my iPhone using Tapatalk

[SportsterDoc]

Keep in mind we know about the EOT and idle speed when it is disconnected. A couple of guys then changed the EOT and the idle problem did not go away.

Good to know.
Was resistance checked on wiring from EOT to ECU?
Probably not an issue for the G/O to A18, since it is a common ground for EOT, plus O2, MAP, TP and IAT.

The R/Bu to B217 should be well under 0.1 ohm.
Concern would be voltage drop.

Might want to compare R/Bu voltage at EOT and then at the ECU.

My bike has been on a high idling kick. Right about 1400. A little irritating


Sent from my iPhone using Tapatalk

I am a newcomer to this forum, so I am just starting to come up to speed, but might be able to help with some electrical diagnosis.

a. How many miles?

b. Type of riding? such as short trips which may lead to carbon build-up

c. High idle each time it returns to idle? If not, under what conditions?

d. If this were a Sportster, I'd suggest checking the rubber intake boots at carb or throttle body for leaks (very frequent issue). On the pre 2007 Sportster carb models, check the vacuum lines to vacuum operated petcock and VOES. So, on the CB, what are potential sources for a vacuum leak? https://www.bikebandit.com/oem-parts/201...#sch848000

[Lord Popgun]

To tell you the truth Doc, I don’t think any real troubleshooting has been done by anyone. At least not what I would do as a technician, or you as a bike repair specialist.

I wish we could find a common cause for this. So far the fixes have been all over the place. Some had actual failures (at least one IACV) and some cured the problem without really determining the failure (think Rico and the dealer changing out the throttle body), or even a software update for one member somewhere in Europe (Honda of America says there is no update).

As member’s bikes develop the problem, they don’t want to read 56 pages of comments (don’t blame them) and thus the same info, like the EOT affects idle, come out. Yes I know, it COULD be the problem that bike.

[SportsterDoc]

To tell you the truth Doc, I don’t think any real troubleshooting has been done by anyone. At least not what I would do as a technician, or you as a bike repair specialist.

I wish we could find a common cause for this. So far the fixes have been all over the place. Some had actual failures (at least one IACV) and some cured the problem without really determining the failure (think Rico and the dealer changing out the throttle body), or even a software update for one member somewhere in Europe (Honda of America says there is no update).

As member’s bikes develop the problem, they don’t want to read 56 pages of comments (don’t blame them) and thus the same info, like the EOT affects idle, come out. Yes I know, it COULD be the problem that bike.

I have not read the 56 pages, either!

My first thought is a vacuum leak, but I do not know how likely that is on the CB. That can be checked by applying an unlit propane torch at possible areas and listen for a change in idle speed. Some folks like WD-40, but it is messy and some WD-40 is reported to have a non-volatile propellant.

If the EOT is a possible suspect, then we need:

1. Resistance and/or voltage values at various temperatures from the factory service manual.

2. Forum members with the issue to:
a. provide EOT resistance values.
b. provide voltage output values, both at EOT and at the ECU. If not familiar with a multimeter, guidance can be provided.

Sometimes the process can be prolonged, as in the case of this thread on which I was only of minor help: http://xlforum.net/vbportal/forums/showt...wer+supply ...but it was solved.

There is a 300+ post thread that was fixed by cleaning a chassis/harness ground to the trans: [url=http://xlforum.net/vbportal/forums/showthread.php?t=1891463&highlight=sportsterdoc&page=36]http://xlforum.net/vbportal/forums/showt...oc&page=36

Has anyone reported any codes associated with this issue?...guess I need to read the entire thread!

[Lord Popgun]

As far I know, no codes set, except for the recent unseated pin on a TPS connector. And due to costs, no substitution of the ECU either.

We do know that having Don Guhl flash the ECU for RPM and max speed changes do not cure the problem.

[Cormanus]

To tell you the truth Doc, I don’t think any real troubleshooting has been done by anyone. At least not what I would do as a technician, or you as a bike repair specialist.

I wish we could find a common cause for this. So far the fixes have been all over the place. Some had actual failures (at least one IACV) and some cured the problem without really determining the failure (think Rico and the dealer changing out the throttle body), or even a software update for one member somewhere in Europe (Honda of America says there is no update).

As member’s bikes develop the problem, they don’t want to read 56 pages of comments (don’t blame them) and thus the same info, like the EOT affects idle, come out. Yes I know, it COULD be the problem that bike.

This was beardywierdy in the UK.

[emptysea]

Ok. Gonna jump in here without ever having read extensively about the idle problem. Looking for a quick y/n answer to the following:

The idle on my new 2013 has a tendency to fluctuate between 1,000 and 1,100/1150 rpm when I’m stopped at a stoplight. Doesn’t happen all the time. Is the “idle instability” of which you are speaking?

[Lord Popgun]

No MTC, not really. They report like a low of 500 and high of 1400-1500. Maybe somewhat higher. I don’t remember the exact numbers but they are in the thread.

Mine does pretty much what yours does. I don’t pay it any mind.

[Ben70_imp]

+1 what popgun says. I think the "real" idle fluctuation affects '14's. Mine does what yours does, occasionally.

Ben

[Cormanus]

+2 to popgun’s comment.