CB1100 Idle speed instability problem

pdedse_imp said:
max_imp said:
Nachodaddy_imp said:
Max, just to verify, the resistors in post #1326 you identify as 220 ohm, and the ones you settled on in post # 1355 are 330ohm, right? And the ones I should install are the 330 Ohm? Or does it really matter?
Thanks again.
PS, I won't try this out until probably late September when the temperature in my garage drops below 90F (or 30C).
Completely understand Nacho, all in good time.
The resistance of one of the two windings of the iacv is around 100 ohms, the ecu checks this value constantly and if it decides the iacv has an open circuit it sets a code ( orange cel ) and puts the engine in " limp home mode" ; 5000 rpm limit.
So the ecu checks the current through the iacv windings, the minimum value resistor is 390 ohm before it sets an alarm, so any value resistor between 100 and 390 ohms is sufficient for the ecu to not set a code, the voltage across the windings is 12 volts according to my oscilloscope, so at 100 ohm the current flow is; 12:100=120 mA with a 50% duty cycle during iacv activation which is o,72 watts ( at 50% duty cycle ) for short periods of time.

So a 1 watt resistor of 100 ohm would work fine, but the same result can be achieved with a 390 ohm resistor, the power dissipation would now be; 12v x 0.03 A= .036 watts.
I tend to choose to do the job with minimal current draw but still reliable so i chose the 330 ohm resistors since they are also used to load the o2 sensor heater when unplugged, ( the ferret's o2 mod ) so it is a bit of a universal value.

So anything between 220 and 390 ohms will work equally well provided the power rating of the resistor is 1 watt, smaller than that means the reliability is compromised and the wire size of the resistor leads becomes too small to fit reliably in the connector,( 0.6 to 0,7 mm., too big a resistor would have larger wire diameters and be more difficult to insert into the connector and the connector's contacts would be splayed out too far in case it had to be re-connected to the iacv.

The 1 watt version i used fitted nicely into the connector if inserted 10 millimeters into the body of the connector, initially i did not insert them deep enough and the orange cel lit up so i re-inserted them a bit deeper at 10 mm.

Long story but now you know why .
Max, your willingness to perform exploratory surgery on your bike when you don't have the problem yourself is admirable. This makes me wish I still had my 2014 standard (which had the high idle problem) so that I could test this fix to see how it works...almost wish, I mean.
....Max, your willingness to perform exploratory surgery on your bike when you don't have the problem yourself is admirable. ......
Bazbro_imp said:
Yes, you're extremely helpful, Max, on this and other matters, I've noticed. Top man! :thumbsup:
^+1^ :thumbsup::thumbsup:
 
Bazbro_imp said:
Yes, you're extremely helpful, Max, on this and other matters, I've noticed. Top man! :thumbsup:
^^ :thumbsup:
 
Thank you, Max. I understand much better now. I love learning new things at my age and this problem has become a blessing in disguise only because you are there with very creative ideas and a brilliant understanding of how this all works. I will keep you posted on my progress.
 
Very good Nacho, i'm glad you get it.
The prize for me is the smile on your face when it works for you and you then have your bike back to enjoy.
.
Also hope that some of the affected members can go back to their dealer and say " i fixed the problem permanently for one dollar " and then NOT tell them how it was repaired......" it's a trade secret ".......justice served:P

You guys had to put up with a lot of unnecessary grief, obviously not fair treatment to you and that is not what you paid for.

Thanks for all the nice comments, it's appreciated.
 
riceburner_imp said:
So, anybody trash the fuel injection and replace with carburetors yet ?
As the owner of a 1995 Triumph Daytona 1200 which plagued me with fueling problems for a year I am really happy with the fuel injection on the CB. :thumbsup:
 
Guys, update. My lazy butt finally got the resistor mod done.

I've been riding with two 330ohm 1w resistors stuck in my IACV plug for about a week now.
My experience:
On startup, bike kicks on, and has a considerably lower idle than before, around 900-1000rpm. Prior to the mod, it was consistently idling at 1200+rpm, even after warm.
A short ride around the neighborhood for a couple miles, the idle does not change and rev high, and still runs like a normal motorcycle.
Once I get some miles in (I commute 20mi both ways during the week), and the bike heats up, it starts running just about the same without the mod, revving high while in gear with the clutch pulled in, revs ramp up when letting the clutch out, and only drops the revs when putting the bike in neutral.

I'm not sure if the resistors are heating up too much and losing their ability to..... resist?

I haven't tried any other resistors yet, as I wanted a baseline on how this would perform over a week of riding.

So unfortunately the resistor mod has not 100% fixed my issue, maybe I'll bump up the resistance and see if there's a change.
 
whizzle_dizzler, I am glad you tried this fix and I hope you can eventually get it to give you the results you want.
On my 2013 standard, my final and complete fix was to replace the ECU, or the PGM-FI unit.
Original part number is: 38770-MGC-A23, however, when I put that number in at Partzilla, the number changed on the screen to 38770-MGC-A24, which is what they sent me.
I see ads for the 23, but I think the 24 might be an improved version and mine is working the way it should be. It is not cheap (Partzilla is the best price) but it works and it is easy to replace.
Best of luck and keep us informed.
:biker:
 
There was just a post by another guy who is looking into a cable to be able to tune the ECU.

If he can read / write the file- then he could read a '24' box and flash it to the older boxes for everyone.
 
GoldOxide_imp said:
lol - over the years I have formed a perception that every time max is up to the challenge to solve a forum question, some CB1100 will get a quick teardown later that day.

I am curious the day a like question is asked:

" ... max? The main journal counter-masses, what are their weight? ... "

Max: " ... uh, that will take me some time. Let me get back to you after my egg salad sandwich ... "

:)
GoldOxide, I agree. Max is incredible. I believe he deserves some kind of an award from this forum for all the support he has provided to so many of us.
 
For the last year or so I've been reading about this, glad I didn't have this problem. Now, I think it has caught up to me. Just today returned from running an errand, and right in front of my garage the engine died. Restarted, revved a little bit, closed the throttle, engine died. My milage is a tad over 7k. I should say mine is a 2013.
 
Charlie Bravo_imp said:
For the last year or so I've been reading about this, glad I didn't have this problem. Now, I think it has caught up to me. Just today returned from running an errand, and right in front of my garage the engine died. Restarted, revved a little bit, closed the throttle, engine died. My milage is a tad over 7k. I should say mine is a 2013.
If you can't get it to idle at all, disconnect the trottle position sensor (TPS) on the left just about where your knee rests. It won't rev over 5,000, but should run fine otherwise.
The TPS is easy to disconnect and re-connect (be gentle) and see how it runs after you run it that way for awhile.
 
Good idea's gentlemen, i'm watching with interest:thumbsup:

Some of you may remember a video from asia where the mechanic did the same thing with what i presumed was honda software, who knows?
 
Charlie Bravo_imp said:
For the last year or so I've been reading about this, glad I didn't have this problem. Now, I think it has caught up to me. Just today returned from running an errand, and right in front of my garage the engine died. Restarted, revved a little bit, closed the throttle, engine died. My milage is a tad over 7k. I should say mine is a 2013.
Ah crap. :s
 
try cycling the emergency stop switch in the right hand grip a couple of times
 
1973cb750_imp said:
we could try like dubs said and flash one with a 14 tune see if this issue goes away would be a test to try might be a fix


It's not 'a' '14 file- Honda has updated the part #'s (which means software update) on both the '13 & '14 bikes..

If we can find someone who has a new part #- we then will have the new software to look at.

2013 old part # and new- 38770-MGC-A23 38770-MGC-A24

2104 old part # and new- 38770-MGC-A42 38770-MGC-A43

...and yes, according to Honda's technical articles on the 2014 6-speed- they DID make changes in the tuning between the 2...
 
.key off, engine not running. Big red emergency kill switch right switch assy, click it off and back on a few times. Then leave it in run position and you should hear fuel pump cycling when you turn key on. They get corroded over time and weather.

I had the same issue back in January and talked about it in a thread called " May have a problem".

May have a problem

knock on wood have ridden it 1/2 dozen times since without an issue. Waiting on better weather to ride it more. Riding the NC while it's nasty out.

Edit: I don't think it matters if the ign key is on or not.
 
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