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+--- Thread: CB1100 Idle speed instability problem (/showthread.php?tid=4140)
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RE: CB1100 Idle speed instability problem - whizzle_dizzler_imp - 05-23-2022
Hey PowerDubs, you mentioned that there are "plenty of places" that would allow me to test a new part, and return if it doesn't work? Since you mentioned it, do you have a parts source that will back that claim up?
I don't mind dropping $700 on a new ECU if that's all it is. I can do an ECU swap in a few minutes. I'll lose less money fixing the bike than trading it in. However, betting that a new ECU will fix it isn't good enough for me.
(05-22-2022, 07:41 AM)PowerDubs_imp Wrote: Well sounds like you already talked yourself out of trying- but there are plenty of places you can buy an updated ECU from online and return it if the problem still occurs.
RE: CB1100 Idle speed instability problem - PowerDubs_imp - 05-23-2022
You can always return on Ebay- https://www.ebay.com/itm/184788087557#rpdCntId
And Revzilla is really good with returns as well- https://www.revzilla.com/oem/honda/honda-38770-mgc-a24-pgm-fi-unit?sku_id=10001935
But if you want to save a lot of money, I would buy it here- https://www.partzilla.com/product/honda/38770-MGC-A24
Of course Revzilla will price match it.
I'm sure there are more place but no need to dig as those will suffice.
RE: CB1100 Idle speed instability problem - whizzle_dizzler_imp - 05-23-2022
Thanks for the response!
Interesting, I assumed those outlets would have some sort of stipulation for the return of electronics such as an ECU. I'll look into it and if everything's straight, I might just buy one and see what kind of result we can net.
RE: CB1100 Idle speed instability problem - PowerDubs_imp - 05-23-2022
Like anything else in the world- there are technicalities to anything.
Like pulling up to a cop, rolling down your window- and asking him if your license plate frame is illegal.
Don't ask, don't tell.
Just don't bang it up / scratch it.
RE: CB1100 Idle speed instability problem - whizzle_dizzler_imp - 05-23-2022
Yeah, I just read their returns page.
I follow ya.
RE: CB1100 Idle speed instability problem - Enzofour_imp - 05-23-2022
Thanks Max, but I need a clarification:
do the tubes of the vacuum gauge connect to numbers 1 or numbers 3?
http://godiamocela.altervista.org/corpi_farfallati.pdf
RE: CB1100 Idle speed instability problem - max - 05-24-2022
Enzo there are 4 calibrated gauges required together with the knowledge to deal with the interaction of the iacv positions.
From the question i think you may not have done a carb/ throttle body sync before, so before changing anything i would suggest to watch several yt video's to find out what's involved, how to do it and why.
Throttle sync is only required when the engine is warm and at idle, there is no other reason to adjust the sync adjustment which is why Honda does not supply service info, they want to avoid the risk of getting it wrong which is easy to do, the adjustment screws are not fixed like the old carburettors so by adjusting too much you can drift out of range and end up with a rich or lean mixture.
With carburetors you adjust the amount of fuel mixture, with a throttle body you only adjust the amount of air per cylinder, there is a difference.
For instance when i bought my cb919 the engine sounded like a harley at idle, the engine only ran on 2 cylinders, it took me a while to work out why, and after syncing the throttlebody with the 4 gauges it started to run like it should have; somebody mis-understood what they did and got it wrong.
Once i had the vacuum gauges installed and started the engine it was very apparent that the sync was off.
All four cylinders have the same capacity so they produce the same amount of vacuum at each intake stroke at the intake when the valves open, this amount can be measured with 4 individual vacuum gauges and adjusted so they read the SAME amount of vacuum supplied through the iacv and adjusted ( equalized ) by the 4 screws under the throttle body.
As soon as the throttle is opened slightly the butterfly valves and the tps start doing their job and the idle screws are no longer of any importance, they are only required when the butterfly valves are closed.
You can then verify this by using a piezo electric pressure sensor in the exhaust and watch the pulses it produces with each exhaust stroke which should be equally the SAME, you do need an automotive oscilloscope for this check so you can record and watch the pulse train.
Hope this helps.
My advice; if there is no problem don't introduce one.
With all respect for your ability and thanks for all your help, i appreciate it; cheers
RE: CB1100 Idle speed instability problem - PowerDubs_imp - 05-24-2022
"My advice; if there is no problem don't introduce one."
Sage advice quite often.
RE: CB1100 Idle speed instability problem - peterbaron - 05-24-2022
(05-24-2022, 06:04 AM)max_imp Wrote: Enzo there are 4 calibrated gauges required together with the knowledge to deal with the interaction of the iacv positions.**
From the question i think you may not have done a carb/ throttle body sync before, so before changing anything i would suggest to watch several yt video's to find out what's involved, how to do it and why.
Throttle sync is only required when the engine is warm and at idle, there is no other reason to adjust the sync adjustment which is why Honda does not supply service info, they want to avoid the risk of getting it wrong which is easy to do, the adjustment screws are not fixed like the old carburettors so by adjusting too much you can drift out of range and end up with a rich or lean mixture.
With carburetors you adjust the amount of fuel mixture, with a throttle body you only adjust the amount of air per cylinder, there is a difference.
For instance when i bought my cb919 the engine sounded like a harley at idle, the engine only ran on 2 cylinders, it took me a while to work out why, and after syncing the throttlebody with the 4 gauges it started to run like it should have; somebody mis-understood what they did and got it wrong.
Once i had the vacuum gauges installed and started the engine it was very apparent that the sync was off.
All four cylinders have the same capacity so they produce the same amount of vacuum at each intake stroke at the intake when the valves open, this amount can be measured with 4 individual vacuum gauges and adjusted so they read the SAME amount of vacuum supplied through the iacv and adjusted ( equalized ) by the 4 screws under the throttle body.
As soon as the throttle is opened slightly the butterfly valves and the tps start doing their job and the idle screws are no longer of any importance, they are only required when the butterfly valves are closed.
You can then verify this by using a piezo electric pressure sensor in the exhaust and watch the pulses it produces with each exhaust stroke which should be equally the SAME, you do need an automotive oscilloscope for this check so you can record and watch the pulse train.
Hope this helps.
My advice; if there is no problem don't introduce one.
With all respect for your ability and thanks for all your help, i appreciate it; cheers
(05-24-2022, 06:09 AM)PowerDubs_imp Wrote: "My advice; if there is no problem don't introduce one."
Sage advice quite often.
Agree with both...if NFF = do not tinker
RE: CB1100 Idle speed instability problem - Enzofour_imp - 05-25-2022
(05-24-2022, 06:04 AM)max_imp Wrote: Enzo there are 4 calibrated gauges required together with the knowledge to deal with the interaction of the iacv positions.
From the question i think you may not have done a carb/ throttle body sync before, so before changing anything i would suggest to watch several yt video's to find out what's involved, how to do it and why.
Throttle sync is only required when the engine is warm and at idle, there is no other reason to adjust the sync adjustment which is why Honda does not supply service info, they want to avoid the risk of getting it wrong which is easy to do, the adjustment screws are not fixed like the old carburettors so by adjusting too much you can drift out of range and end up with a rich or lean mixture.
With carburetors you adjust the amount of fuel mixture, with a throttle body you only adjust the amount of air per cylinder, there is a difference.
For instance when i bought my cb919 the engine sounded like a harley at idle, the engine only ran on 2 cylinders, it took me a while to work out why, and after syncing the throttlebody with the 4 gauges it started to run like it should have; somebody mis-understood what they did and got it wrong.
Once i had the vacuum gauges installed and started the engine it was very apparent that the sync was off.
All four cylinders have the same capacity so they produce the same amount of vacuum at each intake stroke at the intake when the valves open, this amount can be measured with 4 individual vacuum gauges and adjusted so they read the SAME amount of vacuum supplied through the iacv and adjusted ( equalized ) by the 4 screws under the throttle body.
As soon as the throttle is opened slightly the butterfly valves and the tps start doing their job and the idle screws are no longer of any importance, they are only required when the butterfly valves are closed.
You can then verify this by using a piezo electric pressure sensor in the exhaust and watch the pulses it produces with each exhaust stroke which should be equally the SAME, you do need an automotive oscilloscope for this check so you can record and watch the pulse train.
Hope this helps.
My advice; if there is no problem don't introduce one.
With all respect for your ability and thanks for all your help, i appreciate it; cheers
Ciao Max, come puoi vedere non sono proprio un principiante
![[Image: 5efde316e31cb5dc6054cfb30e34aa9c.jpg]](https://cb1100forum.net/forum/uploads/imp/202205/5efde316e31cb5dc6054cfb30e34aa9c.jpg)
Ma questo era un motore a carburatori, sui corpi farfallati si sono un principiante.
Il mio CB1100 non ha problemi, ma vorrei sapere dove precisamente collegare i tubi del vacuometro perche ci sono diversi tubi sul corpo farfallato e non vorrei sbagliare.
Mi piacerebbe controllare se le leggere vibrazioni al manubrio e agli specchi, che ho a motore caldo e in folle, sono fisiologiche o รจ il minimo non perfettamente alliniato.