Hunting rpm

And why? Never heard of that procedure before.
 
I should have been more clear in my post. This is not CB1100 specific, however this is something I have done on other bikes before to clear up issues that seemed to originate from the electronics.

On many vehicles with an on-board computer, you can soft reset the ECU by disconnecting the battery and holding down the brake lever to dissipate any remaining charge. While this won't delete any codes, it usually erases all vehicle specific data, like any driver-learned behaviors.

This might not make a difference, this might make a world of difference. It's an easy procedure to complete and there is no downside to completing it. Lastly, I apologize for stirring the water here. Not trying to cause any issues with anyone's ride.
 
No need for an apology, John. I hadn't heard of this before and it seems others hadn't either. Good information to have and I for one will be interested to hear the results if anyone tries it on a CB1100.
 
Yes, at first when you talk about the brake lever, it seems like a very bike-specific set of steps. But when you remind us that the brake is just to drain any last bit of charge out of the system, the whole procedure comes into focus. Thanks, John.
 
Idle speed update: I replaced my battery today because the original battery tested bad (bike failed to restart when I shut it off in an intersection because I was tired of the 1,500 RPM idle at the stop light), and now my high RPM idle problem is gone! I am NOT saying that replacing the battery cured the problem, because it may just be a coincidence, and my high/low RPM idle problem has come and gone before. I only rode it around at slow stop-and-go speeds for 10 miles because it was beginning to rain, but at each stop it returned nicely to a 1,050 RPM idle. I am as baffled with this as you who are reading this, but I am just reporting the facts. I was all set to replace the IACV, but now I will hold off (John, the sound of my IACV when I turn the key on is still much quieter than yours with the new battery, but I think yours sounds the way it should, and mine doesn't for some reason). I will keep this thread updated, but the bike will remained parked after tomorrow for a while as we will be out of town - hopefully it won't be raining tomorrow and I can put some more miles on it.
 
Dave, I'm happy to hear that the issue has disappeared. Hopefully this is a permanent resolution, as my bike never reverted back to regular idle (and had a faulty IACV motor). I'm thinking maybe yours was getting low voltage from the battery? Just hypothesizing.

Here's to a perfectly idle motorcycle. :)
 
My 2013 CB1100 w/ 19,000 flawless miles hadn't been ridden or started in almost 3 weeks and battery for first time ever was not cranking the starter as vigorously as usual (original battery 3 1/2 years old). It took about half dozen attempts and within 3-4 minutes it started but idling at 2000 rpm. A few rides later (and trickle charge) it starts instantly still idled at 2000 cold, then 1200 warmed up. It also idled higher in gear than in neutral! Never stalled btw. Did the key on and twist throttle routine and it idled correct again. I am getting a new modern lightweight battery and theorize a weak battery caused this issue on mine and MAYBE other CB1100's.
The computer on modern bikes is always draining the battery even while key is off. Clock, etc. Makes sense a healthy battery is part of the equation.
 
This could explain why people start to get this problem suddenly after a year or two of trouble free riding, when their battery looses power.
I also, along with others have only had the problem after riding thru town for 20-30mim, at low revs. At very low revs the alternator may not be producing enough power to keep the battery topped up enough and it throws up a problem.
Just Sayin....
 
Does this annoying problem hurt the motor or other components in anyway???? I live in Florida, have had the bike since September. It just started this issue ones the weather got cooler. I have noticed that she purrs when it's warm out.
 
Macenthor_imp said:
Does this annoying problem hurt the motor or other components in anyway???? I live in Florida, have had the bike since September. It just started this issue ones the weather got cooler. I have noticed that she purrs when it's warm out.
I've had problems with mine for over a year and it hasn't caused me any other problems that I know of. If I turn the ignition off then restart the bike, the problem goes away. Odd I know....

Mine has the problem in hot and cold climates, dry and damp... for me, it's all about dribbling along on low revs for a period of time.

Dave reported recently that he changed his battery and everything was good again. Could have been a coincidence, as it's an intermittent prob. but sounds like a few others have had the same issue as their battery gets weak. I'll be changing mine soon and I'll see what happens.
It would be nice to know why tho. I'm also waiting for my Honda dealer in the U.K. to get back to me with news of the updated ECU map.
Shame, it's a nigling problem on an otherwise reliable bike. It's easy to spot tho and fairly predictable. The power cycle seems to sort it....
 
Interesting. Sometimes restarting a computer solves a problem but other times a "cold boot" is necessary. Have you tried disconnecting the battery for 15 minutes or so then reconnecting? Disconnecting the battery should clear any corrupted code or fragmented memory from the ECM computer(s) and force a reload of a "clean OS" from permanent storage.

If this "cold boot" doesn't work, then the weak battery theory is probably a good one.
 
curlyjoe_imp said:
Interesting. Sometimes restarting a computer solves a problem but other times a "cold boot" is necessary. Have you tried disconnecting the battery for 15 minutes or so then reconnecting? Disconnecting the battery should clear any corrupted code or fragmented memory from the ECM computer(s) and force a reload of a "clean OS" from permanent storage.

If this "cold boot" doesn't work, then the weak battery theory is probably a good one.
Update:
My bike was idling at 2200 rpm in gear and 1600 in neutral after trying to start w/ a very weak battery (it sat for 3 weeks or so and battery over 3 years old). Idling did slightly improve when fully warmed up but still funky.
So, I disconnected battery, squeezed brake lever (to discharge any remaining juice in capacitors), charged the same battery, drained the air box vapor collector (somebody here said to do so can help this idle issue; its the short, plugged 90 degree tube in front of air box; it was full of brown liquid that dribbled out), connected battery, turned on ignition, did the throttle roll-on procedure w/ key on before starting, turned key off, turned key on, then started the bike.
Runs as normal, 1400 rpm cold idle (it always did that), go for a ride and it idled at 1050 rpm when warmed up in a couple minutes or a mile or 2. Things seem to be back to normal for several rides now.
Try these home remedies if your bike is idling erratic and post results. Maybe this is the re-boot procedure for a confused ECU w/ a weak battery issue and air box condensation issue.
 
What would be the point in replacing the IACV with an original Honda part? Wouldn't the new one crap out like the one from the factory? Has Honda corrected the issues and there are new IACVs available?
 
Today I experimemted a bit with the tips of 736cc. After performing all the steps in his instruction, the CB did not stayed on its higher idle rev anymore on the 90km long trip.
Whenever I released the throttle, it found its way back to 1050 rev for idleing, as Honda has originally intended and programmed it. So, for now the problem seems to be solved.
Time will tell for how long. I hope forever, 'cause it's been quite a while since the CB had the low idle rev. In the last half year there was no ride, in which the Honda seems not to be fixed at 1.500 for idleing. And I'm still searching for an answer, why it has been so.

Wisedrum
 
So Wisedrum, which tips did you experiment with or was it all of them?
 
As I wrote, I worked on all the tips/steps in the described order. The only thing I left out, was to charge the battery. In my opinion it was strong enough and didn't make a weak impression.

Today follows a second testride, to find out, if something has changed back
to the unnormal idleing. Hopefully not.

Wisedrum
 
Thank you, Rolls!

Sometimefeels it feels, as we live in a land full of mircales and wonders.
Maybe the CB is part of it. May this kind of Honda voodo has cured its disease.

Wisedrum
 
I read through this entire thread and believe the rpm increase during warm up is normal, especially during cool temperatures. The ECU will rev up engine when cold to reach a specified catalytic converter temperature during open loop. Once temperature is reached, the lambda sensor will signal to the ECU to go into closed loop ( normal idle rpm). If you are near the threshold for closed loop and ride off, the catalytic converter will cool off enough to go back into open loop. I have seen this happen on several vehicles, especially on cold mornings. A motorcycle has its catalytic converter exposed to air cooling.
 
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