Really high idle

[max]

Hi chief, it can be daunting to study the long thread so i try to clarify the essentials as and where needed for the newer guys.
Just hope that i don't bore the rest of the crew with repeats, appreciate all your input as usual, all the best!

[SportsterDoc]

Max, you may want to direct Gordo to your TPS tests and throttle calibration

I think you had more than item C in this post

[url=https://cb1100forum.com/forum/showthread.php?tid=8120&page=66]https://cb1100forum.com/forum/showthread...20&page=66

C. Follow TPS diagnostics per pages 5-23 thru 5-25 of the FSM. Note comments in posts 615, 618 & 622, especially see Max's post 632 regarding TPS output test.

If output is not 0.5 VDC, loosen fasteners (ignition on, engine NOT running) and rotate TPS to obtain 0.5 VDC, throttle closed. After adjusting TPS throttle closed output, do a throttle calibration with ignition on, engine NOT running, by SLOWLY opening and closing throttle, 2-3 times.
Post 615 & 618
[url=https://cb1100forum.com/forum/showthread.php?tid=8120&page=62]https://cb1100forum.com/forum/showthread...20&page=62

Post 622
[url=https://cb1100forum.com/forum/showthread.php?tid=8120&page=63]https://cb1100forum.com/forum/showthread...20&page=63

Post 632
[url=https://cb1100forum.com/forum/showthread.php?tid=8120&page=64]https://cb1100forum.com/forum/showthread...20&page=64

Also check ALL vacuum hoses and Ts are intact.

[dave]

If the piston was too far into the barrel it would re-align itself over the next few startup cycles to the position the iacv is happy with, like 2 steps forward 4 steps back, it will always find the back stop.

Interesting. If there is no feedback from the IACV to the ECU then how does the above happen? Does this mean that if Gordon accidently didn't completely thread the cylinder onto the IACV drive shaft during installation then the IACV will automatically adjust to find the back stop?

[max]

Hi Dave, good question, if the barrel was set too deep into the cavity the bike would not run at 1800 rpm since the opening would be restricted
( all other things being equal ).
here is the iacv body removed, look at the two openings at the bottom of the cavity and you can see the iacv piston sitting halfway the opening where he points his little finger at;
https://www.youtube.com/watch?v=_asKPXxuHbQ

[max]

Just found Pavel's video and made a slow motion part of the iacv operating on a cold engine startup.
Notice the shaft spinning over 5 times more to open than to close with a cold engine,
this ensures that the iacv is at the end of the open stroke every time and the function of the friction clutch in the piston.
https://www.youtube.com/watch?v=0ro0uNGhAKw

If you search "cb1100 iacv you will find 7 video's with info on the iacv operation;
https://www.youtube.com/results?search_q...b1100+iacv

I keep noticing in Popgun's video with the oscilloscope that the pulses on startup are wider than during operation, my
assumption is that the energy is just sufficient to move the iacv when it is new but once exposed to heat it just loses the battle, just my 2 cents....
Hope this helps.

[Gordo_imp]

I am gonna tear everything back down this weekend and re check to make sure everything is lined up correctly with the iacv. I think it is, just want to make sure.

Titus 2:13
2013 HONDA CB1100
Thank you guys again for all your help! I really do appreciate it. I just tried to up load a video, but it's too large.

Titus 2:13
2013 HONDA CB1100

[GoldOxide_imp]

Pretty cool max.

[dave]

Hi Max, and all. Is it possible to disconnect the IACV from the ECU and control it manually (electronically), just to check its operation? Could this be done relatively easily? This could help determine if the IACV is moving, and possibly determine if the ECU is sending a proper signal.

[Gordo_imp]

I know this weekend when I had it all apart again I was checking for leaks and making sure everything was tightened down and secure. Fitting the iacv was daunting task. Trying to line it up and sliding it in. While everything was apart I tested both iacvs. I placed tape on the new iacv and left the old the same. I checked to make sure both were operating. Both iacvs reacted the same when I turned on the ignition.

Titus 2:13
2013 HONDA CB1100
Also by chance does anyone know what part or part number is the automobile equivalent of the CB1100 TPS? I am 300+ posts in on the 1237 post irregular idle thread. I recall some one mentioning there was one, but I dont recall the manufacture or part #
I would really like to test this theory because disconnecting the tps on my CB brings my idle down to 1050 rpms

Titus 2:13
2013 HONDA CB1100

[SportsterDoc]

See the post 82 links
The Honda Rune Forum has posted a TPS replacement for the Keihin JT6H TPS: 16060-MBZ-A11, $114.29 from honda. This is for a 2006 CB600F. The Rune Forum posted that this sensor is a Keihin JT6H, but we have not yet verified compatibility

Follow TPS diagnostics per pages 5-23 thru 5-25 of the FSM. Note comments in posts 615, 618 & 622, especially see Max's post 632 regarding TPS output test.

If output is not 0.5 VDC, loosen fasteners (ignition on, engine NOT running) and rotate TPS to obtain 0.5 VDC, throttle closed. After adjusting TPS throttle closed output, do a throttle calibration with ignition on, engine NOT running, by SLOWLY opening and closing throttle, 2-3 times.