CB1100 Idle speed instability problem

[Lord Popgun]

Yes, same part

 

[beardyweirdy@me.com_imp]

I get a low MPG of 30-33 on my daily commute, have since 2014. In less stop & go it goes into the 50's. Beardy if you want to have beer together in Seattle let me know. Jonz

Thanks Jonz,

If our shaky schedule makes it to Seattle... I'll keep you posted.
I'll no doubt need a beer or two by then.
With regard to the MPG, to be fair, I do have a PCv that needs a tune. It was set up when I didn't have the bike sorted and it could be running rich.

Once I'm back I'll get it on the Dyno and have it tuned. Hopefully that with sort it out.

It's also geared lower, had the ECU/ECM ;-) flashed and has a free flowing air box, pipe and bigger throttle body inlets.... I'll report back when it's tuned.

 

[ericlo69_imp]

Update:
Here in Taiwan, recently HONDA released new (revised) ECU program to solve CB1100 idle speed problem; some owners start to send their bikes to dealer side for new ECU program uploading. (BUT there is not RECALL from HONDA Taiwan dealers). One owner mentioned that his bike (EX model, Throttle body assy has been replaced before because of idle speed unstable) is getting smoother and more powerful after uploading.
Just for your reference, and I will keep it updated.

 

[the Ferret]

Good deal, thanks for the update erico.

 

[dave]

I've been in contact with the dealer I purchased my bike from. I forwarded them the link to this site, and they we supposed to contact the factory for direction. Here's their latest reply to me:

"As far as California goes, they have yet to release anything to fix that issue. Unfortunately we cannot do anything emissions related that would put the bike out of state compliancy. If we do it would be a $10,000 fine on us so at this point we cannot do anything unless Honda releases a bulletin or recall that meets State and Federal Compliance."

Guess I'll have to contact the factory directly.

 

[dave]

Sent a certified letter to American Honda today concerning the unstable idle problem. I'll post an update as soon as I receive a reply. Does anyone want to bet me their reply won't be "take it to the dealer and have them look at it"?

 

[Cormanus]

LOL. No.

 

[Magnus_imp]

Well... spent the better part of today replacing my Idle Air Control Valve (IACV). To get to it you basically have to take the bike apart from the tail up to the throttle body (Rear fenders, battery, air filter housing, air box). The issue I was hoping it would fix was that my bike always wants to idle high at 1500rpm even when warm. During low speed riding it wants to surge ahead - basically it acts like it always has some throttle applied. I was hoping replacing the IACV would fix this but unfortunately it did not. After a couple minutes of riding the idle actually seemed alright but then a few minutes later back to 1500rpms. Oh well. Any idea?

 

[Ben70_imp]

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

 

[Lord Popgun]

There is a procedure in the service manual for checking the EOT sensor.

 

[Lord Popgun]

The interesting thing about all this is that is doesn't seem like one thing is causing the problem. Some have changed the IACV and cured theirs. One (at least) had the whole throttle body changed and that did it. And some in Europe have had the ECU reflashed with a fix and that seems to have done it. Yet in the US they say, as posted above, that they don't know anything about that. I believe that no one has replaced the ECU. That is a big cost for just a guess, although the manual does suggest that

The EOT sensor apparently plays into it, and I think one guy changed his but it didn't fix the idle problem. An interesting and aggravating problem that may have more than one cause. I wish I knew.

 

[Magnus_imp]

BTW here is what you have to do to your bike to get to the Idle Air Control Valve.

 

[Lord Popgun]

Wow! I didn't realize it was that difficult. Sure enough, in the manual: to remove the rear air cleaner housing, remove air cleaner element, REMOVE THE REAR FENDER A and B and on and on.

What a pain!

 

[Retsel_imp]

Might as well lift the gas cap and stick a new 2017 CB under it! But, probably a different cap anyway.

RLETS, Baby face Sliders, Staintune Slip-on, CB500 Mirrors, smaller led taillight, OEM rear rack, Guhl reflash, handlebar risers, Kawasaki Gaiters.

 

[Magnus_imp]

Now I'm thinking you guys might be right about the EOT sensor. It's less than a $30 part so maybe I'll throw one on this weekend. It's easy to get to at least!

 

[the Ferret]

I'll bet you know more about disassembly of a CB 1100 than any shop tech in this country lol

 

[Magnus_imp]

I'll bet you know more about disassembly of a CB 1100 than any shop tech in this country lol

HAHA. Perhaps. Having been a auto mechanic in a former life and then involved in auto racing working of a clean motorcycle is like a treat. Usually much more pleasant. It actually wasn't all that bad, just took time.

 

[Magnus_imp]

In case anyone is wondering exactly where the IACV is located this is a picture of it. It's right below the fuel rail and just between and above the two right hand throttle bodies. Held in place by a small metal plate retained by two screws with a blue mark.

 

[the Ferret]

Nice clear picture. Thanks, I had no idea where it was.

 

[Mechanix_imp]

Darn! I have read through all the posts on this subject and feel bad for not being in tune with my bike as some of you are...I am with my cars though, not sure why that is. Anyhow, I have a 2014 stantard with an intermittent idle issue but has not stalled. I haven't been able to duplicate the problem, just happens randomly at this point. I would be at a stop and the idle will drop a few hundred rpm lower and come back up just as fast...as if I were slightly blipping the throttle. I know on Honda cars this is a common issue regarding the IACV.

My problem doesn't seem as bad as others but this thread has me paying more attention to this. Maybe I will have to get a video of it as proof.

I appreciate you guys keeping up the posts, has me learning a lot about my bike.