Ducati Throttle Body set up and idle setting for ST4S, ST4, MS4, MS4R, 748, 916, 996

Part 2 of throttle body baseline and set up procedure on an ST4S. Same as what you'd do to an ST4, MS4, MS4R, 748, 916, 996.
Think of this as an accompanying video to the information presented in the TPS setting report - www.bikeboy.org/ducati4vthrott... - for the latter throttle balance and idle mixture setting with engine running parts.
Some of the video I shot for this didn't work correctly - I had files that wouldn't open. As such, some of it is words on the screen unfortunately. As I tend to shoot things like this when the opportunity arises, and then edit them after the job has been finished and gone, I don't get to set scenes up in a measured fashion - which can be hard anyway when you're dealing with an assembled bike - and certainly can't go back and reshoot if required. So this one is a little frustrating in places. Hopefully it'll be of value as is. You get to see some of the issues I run into, and that's as valuable as what you might see when it all goes right I guess.
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[@petervandermeulen6641]

Great video! Love the way you work etc.

[@Hamishleonard]

Hey Brad love these videos. Got an S4r with a cracked engine mount that I’ve got in bits so these videos are great.
Just wondering, will a wideband 02 sensor work for this adjustment?

[@bradthebikeboy]

the wideband sensors have a very fast response time, and will show all the cyclic variations as it was at the time of that particular reading, and you might get 10 or more per second. ime the result is all over the place and pretty useless. the co meter is made for this job, so the reading is damped to be useful. maybe if you ran the wideband in a chamber of sorts taking the sample out of the header under vacuum it'd be more stable?

[@xyesman5519]

Spot on, tx! Any chance a video on tps setting is out?

[@bradthebikeboy]

not yet.

[@bobino9245]

I recall reading somewhere where you stated when checking the CO, that the little copper pipe with the proper 1/8 thread to go into the bung hole was easy and cheap to obtain. Where might one get this?

[@bradthebikeboy]

ducati 887131010

[@BlueBeemerBoy77]

Hi Brad! Would it be more right to adjust the airblades to get the same Co2 for both cylinders rather than using vacuumclocks to get the same flow?

[@bradthebikeboy]

i use the cylinder balance for off idle running. the air bleeds have a very limited range of operation - a few degrees throttle opening and they have little effect from there up. so it's two different circuits as such. but you can do whatever you like.

[@nikosbillis]

What could be the cause for the engine to shutdown if I unplug the horizontal cylinder but when I unplug the vertical one the engine still runs?

[@bradthebikeboy]

the vertical is not firing and it's running on the horizontal.

[@zx9b2]

How does the idle control valve on later models assist in making the bike idle?

[@bradthebikeboy]

as its name would imply, the idle control valve controls the idle speed. specifically, it's a linear stepper motor that moves a tapered plunger in and out of a hole to allow air to bypass the throttle bodies and thereby raise or lower the idle speed, and respond to the impact of engine temp, etc. at ignition on it will go to a default opening as specified in the ecu mapping (not sure if that is adapted over time or not) and once running will adjust its position as it attempts to maintain the target idle speed as specified in the ecu mapping. those target idle speeds vary with engine / coolant temperature, usually raising the idle speed somewhat when cold and progressively lowering the idle speed as it warms up.
as the idle control valve simply allows air to bypass the throttle bodies, it is in effect a variable air bleed system with feedback controlled by the ecu. as such, using the manual air bleeds to impact idle speed can impact the idle control valve's ability to do the same thing, and that may cause issues or move things out of expect ranges. as such, i just don't do it. if it has an idle control valve, then i let the idle control valve do its job.
secondly, as the idle control valve simply allows air to bypass the throttle bodies, that variable airflow also needs to be accounted for with a corresponding variable fuel flow separate to the normal fuel flow in terms of how it is calculated in the ecu logic.
also as a point to make there, the only non closed loop ecu idle control valve model was the mts1000. all the others with idle control valves (2006>) have been closed loop, so the closed loop system would have final control over the fuel flow calculations above.
the 5am marelli ecu has a fuel table (map) of rpm vs idle control valve opening steps, and uses that map to calculate how much fuel to inject. when the throttle is opened and the tps output value increases to the point set in the ecu mapping to signify the throttle is now "open", the ecu stops using the idle control valve map and moves to the main and offset fuel maps. i imagine there is some interaction between the two for transition smoothness, but am not sure exactly how that works.
the conti ecu in the 796 and 1100 monsters and other models uses speed/density control logic (inlet manifold vacuum and rpm) at very low throttle openings, and as the amount of idle control valve opening will affect manifold vacuum, the fuelling requirements due to the varying idle control valve position are intrinsically part of the speed/density map. it's a fairly neat way of encompassing it all i guess, but adds more components.
not sure how the later ones do it, never got that far into their ecus.

[@zx9b2]

@@bradthebikeboy Do you ever come across bikes with reflashed ECUs running open loop, where the idle/cold run map has been lost or interfered with?

[@bradthebikeboy]

@@zx9b2 lost no, things don't get lost from files. but i've certainly interfered with a few.