CB1100 Idle speed instability problem

[SportsterDoc]

My bike is only having the issue in hot weather (90F+) combined with stop and go traffic. Not a single problem since last August though. Last August is also the first time I experienced the symptoms to the extent of the bike dieing.

I'm willing to bet my case is wear or corrosion starting to affect the performance of something rather than defective parts from the factory.

I park indoors at home and outdoors at work. I ride in all weather conditions except snow. My bike gets washed twice a year, if it needs it or not.

Have you checked connections of TPS, EOT and IACV?

 

[Mechanix_imp]

Hi Mech, looking at your part of the spreadsheet i assume that is the video you refer to ( correct me if i am wrong at any stage ).

So the engine is cold, started and idling at 1500 rpm as they normally do, but when you pull the clutch in it idles at 1700 rpm instead,unless the lever is pulled close to the handle and drops back to 1500 rpm ( had to read your explanation 6 times and i think this is what you mean ).

It is possible that because of the cold temperature the engine idles at 1700 instead of 1500 rpm.

Just checked and the switch on the clutch is open when the lever is forward, and closes if the lever is pulled back, you can hear when it operates.
The wiring is hard wired ( not dependant on the elecrtonic control module ) but does provide input TO the ecm.
That means the clutch, neutral and sidestand work to prevent starting even if the ecm is faulty.
The inputs to the ecm are; b22 sstand and b33 nl sw.

To verify if it is the switch you can pull one connector off and confirm the switch is causing the change in rpm.

here is the diagram courtesy of popgun





Question is; has it always been like this in below 55 degrees or is this new behaviour that started with low idle, my guess is it is not related but who knows.

Interesting about the warmup period of 4 miles, do the rpm's gradually lower when the engine heats up or is there a sudden drop and when does the low idle start?

Thanks for checking the clamps.

Well, when I first got the bike I was reading about the issues and was thinking “ glad this isn’t happening to me”... but around 5 or 6 thousand miles on the bike it started.

Actually the opposite of what you read the 6 times...sorry for that. It will cold idle at around 1500 rpm but will increase to 1700 rpm when clutch lever is being released. Clutch is right at the point of grabbing but still no load on the engine. It acts as if I were twisting the throttle as I was letting out the clutch.

As for the warm up, the idle will go down after a mile or so but the idle will still increase when letting out the clutch for four miles or about 10 minutes. There really isn’t a sudden drop , it gradually goes down to 1000 as I ride for a while. I do have a video of when I started it before work this morning (not very cold) but need to get a better one, I will try to load it on YouTube and post a link.

Thanks Mechanix, there seems to be a relation ship with higher temperatures, not clear why for now but you are not the first to link the ii issue to warm conditions.

Could you explain in more detail what happens when the clutch is engaged? is the engine warmed up, does it happen consistently, does the idle return when the clutch is released etc.

It would help your case if you could document the situation with appropriate comment on the video and show them what happens and how often it occurs, even better post it on youtube so everybody can see it, also get some sort of proof that you made the dealer aware of this idle behaviour ( witness ) and when before the warranty runs out, according to my nz dealer Honda do stand behind their product even after the warranty expires but require strong proof to do so.

max

Link to cold idle

Link to warm day ride low idle

 

[max]

Thanks Mech, nice video's and very surprising action on the clutch, from the video it is not clear if the switch is operating to cause the increased rpm effect, is it possible to disconnect the switch and see if any change occurs?

And has this behaviour started at the same time the low idle started?

Thanks for posting the video's they are perfect for us to work with as we are mostly in the dark about the exact behaviour since none of our team actually have the issue ourselves.

max

 

[kennyw]

My bike is only having the issue in hot weather (90F+) combined with stop and go traffic. Not a single problem since last August though. Last August is also the first time I experienced the symptoms to the extent of the bike dieing.

I'm willing to bet my case is wear or corrosion starting to affect the performance of something rather than defective parts from the factory.

I park indoors at home and outdoors at work. I ride in all weather conditions except snow. My bike gets washed twice a year, if it needs it or not.

Have you checked connections of TPS, EOT and IACV?

I have done no troubleshooting yet. I need to wait for warmer weather when I can recreate the issue to verify it gets fixed.

 

[Mechanix_imp]

Thanks Mech, nice video's and very surprising action on the clutch, from the video it is not clear if the switch is operating to cause the increased rpm effect, is it possible to disconnect the switch and see if any change occurs?

And has this behaviour started at the same time the low idle started?

Thanks for posting the video's they are perfect for us to work with as we are mostly in the dark about the exact behaviour since none of our team actually have the issue ourselves.

max

Ok, this morning was a bit cool so I started the bike and had it in neutral, no issue. Put bike in gear and had idle at 1200rpm until I began to let out the clutch lever...up to 1700rpm. I shut off the bike and disconnected the clutch switch, restarted bike and cold idle was 2000rpm. A few twists of the throttle and idle rpm still at 2000 and no reaction with clutch. I had to leave for work so no video to post but I will try this again on another cool morning and start off recording.

 

[SportsterDoc]

I am at a loss to attempt to explain any electrical correlation with releasing the clutch and increased idle speed; other than perhaps the IACV is reacting/over-reacting to increased load?

Before pursuing this, Is it possible that there is zero slack in the throttle cable and your right hand moves slightly as left releases? Have you tried this with hand off throttle? (could not see with vertical video format)

Ambient temperature might possibly affect electrical connections or a vacuum loss.

The EOT (engine oil temperature) sensor is a thermistor. It is very high resistance when coldest, then loses resistance as the temperature increases.

Therefore, if there is a poor/high resistance connection relating to the EOT, the higher resistance could indicate to the ECM a colder operating temperature than actual. If so, the IACV would maintain higher RPMs, as during warm-up.

Even though the IACV operation is a prime suspect in most of the reported idle issues, there may be (instead of or in addition to) poor electrical connection(s).

 

[Mechanix_imp]

I am at a loss to attempt to explain any electrical correlation with releasing the clutch and increased idle speed; other than perhaps the IACV is reacting/over-reacting to increased load?

Before pursuing this, Is it possible that there is zero slack in the throttle cable and your right hand moves slightly as left releases? Have you tried this with hand off throttle? (could not see with vertical video format)

Ambient temperature might possibly affect electrical connections or a vacuum loss.

The EOT (engine oil temperature) sensor is a thermistor. It is very high resistance when coldest, then loses resistance as the temperature increases.

Therefore, if there is a poor/high resistance connection relating to the EOT, the higher resistance could indicate to the ECM a colder operating temperature than actual. If so, the IACV would maintain higher RPMs, as during warm-up.

Even though the IACV operation is a prime suspect in most of the reported idle issues, there may be (instead of or in addition to) poor electrical connection(s).

I knew I should have taken a better video! Left hand on the clutch lever and right hand taking video so no throttle contact. And I know it is hard to tell but I was not on the brakes at all and clutch was right at the point of starting to grab but no load on the engine, the bike didn’t even try to move.

I will go through all the connections on a day off of work but I will also try to look at everything else I can get to quickly without taking the bike out of operation...it’s my primary vehicle right now.

I really appreciate all the input I have been reading in regards to this, this is one of the best groups I have been a part of.

 

[max]

Mechanix i think your video's are very educational but the next one can be a bit better and longer, good idea and very good of you to recognize this.

What i also wonder is if the clutch effect works in all gears and neutral or just 1st gear ( both with connected and disconnected switch ) you could comment this in the video.
I suspect this behaviour is possibly programmed into the ecm hence the gear test.

You are doing great, we can come up with enough hints to narrow this down quite a bit but we need your help and i will try to explain why things happen the way they do along the way.

cheers max

 

[dave]

Update: I am performing the four, wire connection inspection and cleaning steps recommended my Max, one at a time. I started with the IACV connection and here are my comments: Connection appeared clean and in perfect condition. I thoroughly sprayed the connectors with electrical connection cleaner and dried with compressed air. I then started the bike with the IACV disconnected to see what would happen. The bike had not been started in several days, but started quickly, and immediately went into an 1,100 RPM idle, which is surprising because it normally goes into a high (1,400 – 1,500 RPM) idle when the engine is cold. This idle speed lasted for maybe 5 seconds, or less, and then dropped to about 600 RPM. I believe it would have stalled, but I blipped the throttle a few times to see what would happen. Each time the idle speed returned to about 600 RPM, and I am sure the engine would have stalled had I not twisted the throttle. I reconnected the IACV and went for a ride. Within three miles the low idle condition returned, so the conclusion of this test is that cleaning the IACV connection does not cure the low RPM idle condition. I will continue testing today by disconnecting and cleaning the remaining three connections recommended by Max, and will report back (as soon as I complete rebuilding and installing the VFR800 forks).

 

[SportsterDoc]

Update: I am performing the four, wire connection inspection and cleaning steps recommended my Max, one at a time. I started with the IACV connection and here are my comments: Connection appeared clean and in perfect condition. I thoroughly sprayed the connectors with electrical connection cleaner and dried with compressed air. I then started the bike with the IACV disconnected to see what would happen. The bike had not been started in several days, but started quickly, and immediately went into an 1,100 RPM idle, which is surprising because it normally goes into a high (1,400 – 1,500 RPM) idle when the engine is cold. This idle speed lasted for maybe 5 seconds, or less, and then dropped to about 600 RPM. I believe it would have stalled, but I blipped the throttle a few times to see what would happen. Each time the idle speed returned to about 600 RPM, and I am sure the engine would have stalled had I not twisted the throttle. I reconnected the IACV and went for a ride. Within three miles the low idle condition returned, so the conclusion of this test is that cleaning the IACV connection does not cure the low RPM idle condition. I will continue testing today by disconnecting and cleaning the remaining three connections recommended by Max, and will report back (as soon as I complete rebuilding and installing the VFR800 forks).

Dave, thank you for faithfully continuing with the regimen and continuing to report.

 

[max]

Thanks Dave nice report, if it is not too difficult to do i wonder if you do the same thing as before by disconnecting the iacv before starting the bike ( iacv is in 1050 rpm running position when the bike is switched off ) and nursing it to warm up to the point where the rpm is stable enough and taking it for a ride to see if the idle is usable without the iacv valve connected.
In other words: because it is now fixed in one ( correct ) position it cannot change idle rpm and mess with idle speed.

Ignore the check engine light flashing.

+1 on Doc; max

 

[the Ferret]

Thanks Mech, nice video's and very surprising action on the clutch, from the video it is not clear if the switch is operating to cause the increased rpm effect, is it possible to disconnect the switch and see if any change occurs?

And has this behaviour started at the same time the low idle started?

Thanks for posting the video's they are perfect for us to work with as we are mostly in the dark about the exact behaviour since none of our team actually have the issue ourselves.

max

Ok, this morning was a bit cool so I started the bike and had it in neutral, no issue. Put bike in gear and had idle at 1200rpm until I began to let out the clutch lever...up to 1700rpm. I shut off the bike and disconnected the clutch switch, restarted bike and cold idle was 2000rpm. A few twists of the throttle and idle rpm still at 2000 and no reaction with clutch. I had to leave for work so no video to post but I will try this again on another cool morning and start off recording.

That's just crazy. Watched the video and never seen anything like that. Why would the idle go up just because the clutch is being let out? (except if you have Suzuki's easy start lol). I don't understand the relation.

 

[PowerDubs_imp]

Just a guess- let the clutch out, rpms drop, system tries to regulate and over compensates because something is out of wack.

Every modern vehicle compensates something like neutral or park to drive.


Sent from my iPhone using Tapatalk

 

[Mechanix_imp]

Mechanix i think your video's are very educational but the next one can be a bit better and longer, good idea and very good of you to recognize this.

What i also wonder is if the clutch effect works in all gears and neutral or just 1st gear ( both with connected and disconnected switch ) you could comment this in the video.
I suspect this behaviour is possibly programmed into the ecm hence the gear test.

You are doing great, we can come up with enough hints to narrow this down quite a bit but we need your help and i will try to explain why things happen the way they do along the way.

cheers max

Thanks, I’m pressed for time in the cool mornings before work but I will be sure to get up early on my day off to try again.

I can tell you it happens in every gear but not in neutral, and seems to take a while to get out of the cold high idle condition...the colder it is the longer it takes. I will comment on the next video or videos with switch connected and disconnected. But I’m running out of cold days here!

 

[Bindir Dundat_imp]

I have a 2009 CBF1000 and also 2012 CBF1000. The 2012 when you let the clutch out, RPM will increase 200 to 300 RPMs. That happens so it'll prevent it from stalling when engaging 1st gear. The 2009 CBF doesn't have that feature. I also read the last few pages on this and nobody mentioned cleaning their negative cable to the body. Sometimes corrosion gives you a lot of Gremlins. The one guy I remember that posted a few pages down changed his battery I wonder if he was able to clean the negative cable to the body so he didn't have any problems after that. The 2009 CBF is notorious for burning out stator. My preventive maintenance is to make sure that the ground cable is always clean and a battery gauge to monitor the stator output. So far, the 2009 is still running good. This thread really interests me because I have a used 2014 with 19000 Km that i'm looking at.

 

[Mechanix_imp]

I would believe this cold idle increase with clutch engagement is a FACTORY deal but it didn't do it in last year's cold days. It came around near the time the hot low idle issue showed up...about 5700 miles. I'm going to tear this thing apart after I get my truck running!

Here is a link to another high idle video...hopefully better than the last one. Temperature in the morning was 42 degrees.

 

[the Ferret]

Mine has never done that, and in 5 years I don't remember anyone on the board mentioning or questioning it either. Have never read it in a road test either by the magazines either or in Honda's designer talk series. I don't think that is normal for our CB's.

Some new Suzuki's do that and they labeled it something like "easy start" or something so that newbies wouldn't stall when taking off.

 

[Bindir Dundat_imp]

Here is a link to another high idle video...hopefully better than the last one. Temperature in the morning was 42 degrees.

My 2012 CBF1000 also does that, it's very normal. I think it's called easy start for newbies.

 

[the Ferret]

Bindir. Watched the video again. Does it do it once it reaches normal idle of 1050 and you put it in gear?

 

[Mechanix_imp]

Bindir. Watched the video again. Does it do it once it reaches normal idle of 1050 and you put it in gear?

No, this issue only happens when it's cold. The other day it was around 70 degrees and it didn't happen, but it was at normal idle speed after I started it and not cold idle. I will check it out some more but I believe when the cold goes away so will the issue. I need to document all I can so when I take it in (under warranty) they can see exactly what I'm wanting fixed. I'm sure they will throw a bunch of parts on it hoping it goes away.