CB1100 Idle speed instability problem

[Sandhog_imp]

My bike also sounds normal.

Most recently I've been having the high-idle issue (1500+ rpms). The mechanic at dealership believes replacing the EOT Sensor may fix the problem. I'm heading down the dealership tomorrow so they can replace the part.

Unplugging the EOT sensor will cure the problem, but then your "check engine" light and the engine temperature light will both be on. I replaced my EOT sensor and it did not cure the problem. BTY - it's a simple, 10 minute job to do it yourself.

Unplugging the EOT sensor will cure the problem, but then your "check engine" light and the engine temperature light will both be on. I replaced my EOT sensor and it did not cure the problem. BTY - it's a simple, 10 minute job to do it yourself.
Dave, I hear you, thanks. The bike is under warranty so I want Honda to work through the diagnostic / repair process otherwise I would just take a gamble and purchase and replace the part myself. I really like the CB1100 but these engine idle issues are the pits.

Unplugging the EOT sensor will cure the problem, but then your "check engine" light and the engine temperature light will both be on. I replaced my EOT sensor and it did not cure the problem. BTY - it's a simple, 10 minute job to do it yourself.
Dave, I hear you, thanks. The bike is under warranty so I want Honda to work through the diagnostic / repair process otherwise I would just take a gamble and purchase and replace the part myself. I really like the CB1100 but these engine idle issues are the pits.
So it seems my bikes high-idle problem is gone since the EOT Sensor was replaced, I've ridden a little over 225 miles in the last couple of weeks, mostly short commutes on back roads with little to no traffic. The idle has been spot-on at 1050 rpm each and every time. The low-idle issue hasn't occurred recently either but then again that was always triggered when riding in heavy stop and go conditions. I guess only time will tell but I'm very happy with the way the bike is running now.

 

[Riko_imp]

Thanks for the feedback. I have money down on a 2017 and expect delivery in early June as it ships May 29th from Japan. I bought the five year warranty for piece of mind but would rather a dealer tech not have to undo anything from the factory for a good long while. Being in manufacturing and having turned wrenches professionally at one point in my life, I feel the factory can do quite a bit better job than most repair shops and prefer their work stay untouched. At least as long as possible.

lol five year warranty, for a Honda that's a lot imo.

what did you pay for that extra warranty?

I just bought a second hand ducati last month and I could only buy 2 years warranty max, at the end I can extend it again and again, but didn't have the possibility for 5 years.

 

[Aka Tsubasa_imp]

Thanks for the feedback. I have money down on a 2017 and expect delivery in early June as it ships May 29th from Japan. I bought the five year warranty for piece of mind but would rather a dealer tech not have to undo anything from the factory for a good long while. Being in manufacturing and having turned wrenches professionally at one point in my life, I feel the factory can do quite a bit better job than most repair shops and prefer their work stay untouched. At least as long as possible.

lol five year warranty, for a Honda that's a lot imo.

what did you pay for that extra warranty?

I just bought a second hand ducati last month and I could only buy 2 years warranty max, at the end I can extend it again and again, but didn't have the possibility for 5 years.

lol five year warranty, for a Honda that's a lot imo.

what did you pay for that extra warranty?

I just bought a second hand ducati last month and I could only buy 2 years warranty max, at the end I can extend it again and again, but didn't have the possibility for 5 years.
Yeah, the warranty might be excessive but if I need a throttle body replacement at $3000 - $3500 I will be glad its there. It will also help if I ever want to sell the bike as the warranty is transferable. I like to sell my bikes off and get new ones every 2-3 years. Kind of a virtual lease program. Although, the CB1100's seem to be a cut above other bikes in build quality and I am hoping this one is a long term keeper.

 

[Magnus_imp]

So... still having the 1500rpm idle problem. I've tried all sorts of things... replacing the EOT, IACV, adjusting the throttle... no luck.

So I tried UNPLUGGING the EOT sensor as some have suggested and the bike won't even start. Just stumbles and dies immediately. Strange it works for others? Are you unplugging it after the bike is warm?

Hey, Magnus! Unplugging the EOT sensor dropped the idle for somebody earlier in this thread, implying a possible bad sensor. This is assuming the bike is programmed to idle up under hot oil temp situations, presumably to increase flow thru the oil cooler. Perhaps the EOT sensor could be ohmed, but it would be nice to have some parameters. Good luck.

Ben

 

[Aka Tsubasa_imp]

Sounds like an old school vacuum leak to me. Spray some carb cleaner around where the throttle body meets the engine while its running. If the idle changes you found your problem. Seems really low tech but its good to eliminate the easy stuff first.

 

[beardyweirdy@me.com_imp]

Dragging up a bit of an old thread here, but...

I'd noticed recently that my Idle speed wasn't as smooth as it was. It was a bit like having an old school choke where it wasn't happy when running from cold. Once warm it's all good, so it's not massive problem. I also noticed that the sound of it operating when you first turn the key was quieter than it used to be.

Thought maybe it was gummed up and though about stripping it down to inspect it.
I had already been thru the diagnostics with a meter, as per the manual and it all checked out in spec.
As the results from the meter were good and it wasn't a massive problem I decided that I was being a fuss pot and it wasn't worth the Agg. of stripping it all down, so I've left it till, it gets any worse.

Reason I'm posting is that I looked up on the parts list how much a new one would cost, if it were knackered, and saw that Honda have changed the IACV on the new 2017 models.
New part number and £160 as opposed to the £106.
Could this be the cause of the problem we've been having?
Pure speculation and gossip mongering but thought it was interesting to change such a part.

 

[Cormanus]

Very interesting, beardy. I wonder whether the 2017 part fits earlier models.

 

[beardyweirdy@me.com_imp]

I thought so...
if it wasn't such a ball ache to get to ID have it out and mesure it up.
It would be a fairly expensive experiment fir anyone still suffering with the idle problem, but could be worth it.
The weathers too good to be spannering and there is riding to be done, but come the winter and the major service, I might do it.

 

[Cormanus]

Yeah, I gather it's been pretty warm over your way. That and long days are pretty good for riding.

 

[beardyweirdy@me.com_imp]

There has been some cracking days... light by 4am and blazing till sundown around 10. Average for you guys but we've been pissing our pants about it

 

[peterbaron]

Hello ALL CB owners,
.....idle speed fluctuation (when fully warmed up)....maybe this maybe that, dealer replaced few parts without any results.. :(

If part is defective = needs replacement. If needs ECM/software reprogramming = YES must go for it.
But let's say your idle is erratic even if ALL components are NOT defective, ECU has the LATEST version, no DTC present, electrical connectors are sound, your bike has NO!!!! mickey-mouse ECU related aftermarket gizmos/modifications, throttle cables are not sticky and are adjusted properly as well as the th. plates, crankcase breather + other one are already cleaned out....what you MAY do next....

ISC or IACV does similar if not identical job in FI system= control idle (through air flow, not fuel) when throttle is closed .
Your throttle plate is closed and its voltage reading is being sent to ECU through TPS . ECU calculates its value ( and other values as well, like engine temperature , injection time, ignition timing.. etc) and continuously tells ISC/IACV to be open more or less to maintain proper idle .
I would check ( as ONE of possibilities) if throttle plate has excessive carbon build up, which prevents throttle plate to go to full closed position and as a result , TPS sends erratic signal to ECM which as a controller sends command to ISC/IACV to open-close-open....++++ and you get idle fluctuation.
In a less likely scenario ISC/IACV , intake valves may have carbon build up as well.

To check your throttle is not going to be so easy due to limited space access but it can be done...and make SURE you check your throttle body when plates are FULLY OPEN.
For my '13 CB with 42K, I regularly use fuel injection cleaner ( to gas tank) 2x a year when gas tank is full and oil /filter change due, drive my bike to empty tank and replace oil/filter = done.
For winter storage , I add FI cleaner (proper amount to fuel volume) when engine is still warm, idle it for a while, turn ignition off and park my bike for winter hibernation.
I always use highest octane rating available at the pump (usually 94 or 92)...'cuz it is LESS dirty than regular ( has less ppm)... I don't even know and care what octane rating owners manual recommends to use.
THIS IS WHAT I DO WITH MY LOVELY CB1100A... you may follow or not, it depends entirely up to you.
I do NOT intend to overwrite service manuals or provide field fix but only a THOUGHT.
All vehicles require regular maintenance as per manufacturer's manual = read yours, please.

Cheers to ALL
Peter
------------------
'13 CB, 42K

 

[dave]

So... still having the 1500rpm idle problem. I've tried all sorts of things... replacing the EOT, IACV, adjusting the throttle... no luck.

So I tried UNPLUGGING the EOT sensor as some have suggested and the bike won't even start. Just stumbles and dies immediately. Strange it works for others? Are you unplugging it after the bike is warm?

Hi Magnus. I unplugged my EOT sensor after the engine was completely warmed up. I pulled off the road when the high-speed idle condition reared its ugly head, turned off the engine and unplugged it. When I restarted it the bike ran better than new. I repeated this experiment three times, each time with the same results. I would reattach the EOT sensor when I put the bike away after riding, but one time I left it unplugged. When I started it the next day it did not start cleanly, like it normally does, and it stalled. I immediately plugged the EOT sensor back in and this cured the problem.

 

[Lord Popgun]

Cured the idle problem?

 

[Cormanus]

More likely the bad start, stall problem, popgun.

 

[dsan1964_imp]

My bike was acting up last night idling at 1300 I turned it on and off did the throttle reset oddly enough when I got home and went right back down to 1000 but it was acting up for about an hour


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[Wisedrum]

Over long periods of time the high idle problem of my CB dispappears. I did'nt do the throttle calibration any more, it start's to become neurotic without any real change of this so to day misfunction. If it reoccurs, which it sometimes does, don't know why although I have my presumptions, I choose an empty straight street, put in the 2. gear and ride the CB full throttle for a short time.
Mostly this will cure the Honda for the upcoming rides.
I don't really like doing so, 'cause I prefer the smooth and low to mid rev riding. But if it's the only thing that helps somehow, I do so once in a while. The Honda despite of this runs well, no other bad items. Good throttle response, good, low fuel consumption. I presume this sometimes high idleing is part of the CB and all its sensors and the kat as a honda engenieer told me, to calm down my worried mind.

Wisedrum

 

[dave]

More likely the bad start, stall problem, popgun.

You are correct Cormanus, the starting problem.

 

[Rolls_imp]

My idle acted up a bit again for a day and then fixed itself. After a 55 mile early morning ride from Belmont to Soquel, I next headed a couple miles done the coast to Capitola. On the way, the bike started to stumble and idle rough or even cut out if I didn't goose it a bit to keep it alive. This has previously been a harbinger of the high idle problem, but this time it just fixed itself later the same day. Couple weeks now and no problem.

 

[Aka Tsubasa_imp]

Has anyone ever verified proper fuel pressure or looked for a dirty in tank fuel filter? Low fuel pressure at idle when charging system voltage is lowest might send the FI system hunting. There is a low probability of occurence but it would be good to rule out any fuel delivery variances. It was one of the first steps in proper engine diagnostics when I was a tech.

 

[beardyweirdy@me.com_imp]

I'm coming round to excepting that it's just one of those peculiarities of the model.
It's not the end of the world and it doesn't seem to be getting worse or causing any major failings.
It'll be interesting to see if any of the 2017 models display the problem.

I've just bought some Lucas Injector Cleaner. Thinking it's so intermittent it could just be build up of fuel deposits. It does seem that without exception turning off then on again always seems to cure it. On start up, the IACV cycles open to close and the fuel pump cycles, I'm guessing building up the right pressure.

Could be this cycling dislodges what ever was causing the issue. Likewise it could be recalibrating a component and curing it that way.

We may never know, so I'm living with it. The bike has many more positives and this is almost the only negative for me, so worth it I reckon.

The Romans used to build known imperfections into their mosaics, as perfection was the prerogative of the gods. I like to think Honda were thinking along those lines when they built in the wonky valve timing but surely not this! It's one way to mentally deal with it ;-)