CB1100 Idle speed instability problem

[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
https://youtu.be/ic9QxN_SEMU

Link to warm day ride low idle
https://youtu.be/_PnA_x66VVM