Quote from: DuciD03 on February 22, 2020, 09:37:05 AM
yes, a fast idle lever … that kind-a acts as a choke ...

I'd say it acts like a twist throttle rather than choke. All the cold start lever does is it rotates butterfly valve in the tb to allow more air. Choke does the opposite as the name suggests, it limits amount of air!

Quote from: pmazdan9 on February 24, 2020, 01:31:22 AM
I'd say it acts like a twist throttle rather than choke. All the cold start lever does is it rotates butterfly valve in the tb to allow more air. Choke does the opposite as the name suggests, it limits amount of air!

Yep.

Quote.All the cold start lever does is it rotates butterfly valve in the tb to allow more air.

No. More throttle, higher TPS, more fuel and air.

Quote from: greenmonster on February 25, 2020, 05:05:26 AM
No. More throttle, higher TPS, more fuel and air.

Can you elaborate?

Principle is the same, both twist throttle and cold start lever are connected to tb and they do the samo job. AFR is adjusted by ECU the same way for both, so yes more air means more fuel of course, but the lever itself just opens the valve and lets more air in. Amount of fuel is controlled by another device. My point was choke reduces amount of air, which is kind of the opposite of what the cold start lever does. Assuming we're not talking about enrichment circuit or other systems people call "choke"

I'm not arguing, just not sure I understand what you mean - I am no expert by all means and still learning about this stuff so please correct me if I'm wrong!

Throttle angle is an input to the computer.  That, along with RPM, temperature and, depending how complex the system, other data affects fueling.  On an engine with an idle control motor idle speed is controlled by the motor allowing more or less air past the throttle.  Assuming the bike is not modified and perfect opening the throttle disturbs the fueling.

Back when Monsters had carbs we (including both me and Ducati) wrongfully used the term "choke".  The choke cable was attached to a device (starter enrichment plunger) that adds the needed fuel for cold start.  Same with old European cars with CV carbs

+1
Yeah, we often use the term choke as a generic term to include carb enrichment devices, fast idle devices, etc coz we're old .

Just to add further confusion, I used to remove choke plates from Harley carbs back in the day, then port them. I left the fast idle detente however, so there was still a "choke" knob and cable to activate fast idle at warm up. I then derestricted the accelerator pump to use as an enrichment device.
Just tryin' to help.

... ... ...



inner-est-in!… ill have to review again when Im less tiered.

…. have a machine with a plunger; and one with a thermal plug....and some more modern ones with electronic doo-hickies ….

… look-in for a manual lever and the screw on fast idle (choke) mechanism off a 02-07 s2r 400-800, Looks like the 750 era fast idle lever would do the trick  ;  . Willing to pay a bit; donors welcome. ebay has lots of options; but ill have to dig to find the bits ...

I was wondering why ducati didn't program ECU to adjust idle on my and other older (?) monsters, as there's an option to set idle in relation to temperature in ECU. Why bother with lever I wondered? I then figured this is the case on FI monsters with no stepper motor, so I read more about these devices. Like howie said it opens a valve to give more/less air, thus increasing idle.

I guess the answer is, because ECU can only add more fuel to increase idle, making the bike idle richer, thus not meeting emission standards Whilst stepper motor adds more air (therfore more fuel as well) so theoretically it does the same job but better as it keeps AFR the same ish. Why didn't they add stepper motor to some FI bikes is another question, my guess is to save money perhaps.

All of the above might be completely wrong, just my thoughts. In any case, I don't care about emissions so my idle is increased by ECU when cold, so I tend to use cold start lever as a cruise control instead

Given the idle control valves list at around $1000 (or used to anyway), it'd be a cost function on cheaper models.  Closed loop models benefit much more from them too.

If your cold idle on an idle control bike is a bit crappy getting into the file and increasing the ignition advance on the idle map can make a real difference to how effectively the idle speed control works.   You might need to get into the breakpoints and idle speed targets to make it super stable, but ignition advance is the key in my experience.

Otherwise, as has been mentioned, get some 800 throttle bodies (before 2007 or so are better) and fit that set up.  You'll need to reset the idle stop to account for the difference in TPS setting at idle.  You'll also need to flash the ecu with an non idle control file too, otherwise the input allocated to the idle control valve opening (there's a specific rpm vs opening fuel map) will make setting up the idle mixture fairly hard I would think - never actually tried to introduce a mess like that.  Using an M1000 based file works just fine in an S2R1000 with the idle control valve disconnected.  the ecu simply doesn't acknowledge it.  You'd need to migrate your S2R1000 values over into the M1000 file.  Shouldn't be that hard.

Quote from: pmazdan9 on February 26, 2020, 01:28:41 AM
In any case, I don't care about emissions so my idle is increased by ECU when cold, so I tend to use cold start lever as a cruise control instead

If your bike has a factory fitted fast idle lever then there is no idle speed control facility via the ecu.  Idle speed is set via the air bleeds and also quite effected by the idle mixture (trimmer setting) if the mixture is enough too lean or rich.

Quote from: Orange16 on February 26, 2020, 02:07:11 AM
If your bike has a factory fitted fast idle lever then there is no idle speed control facility via the ecu.  Idle speed is set via the air bleeds and also quite effected by the idle mixture (trimmer setting) if the mixture is enough too lean or rich.

I assure you there is Check my post here:
http://www.ducatimonsterforum.org/index.php?topic=77937.msg1429780#msg1429780

Factory map has it set to 1000, however ECU is perfectly capable of adjusting idle. I've set mine to idle at 1500 when cold and 1250 when warm - works perfectly fine.

S2R800?  How do you think the ecu controls the idle speed?

Quote from: Orange16 on February 26, 2020, 02:46:31 AM
S2R800?  How do you think the ecu controls the idle speed?

Yes it's '05 s2r800 with cold start lever. I guess it adds more fuel until rpm sensor reading reaches value stored in the map depending on the air temp sensor reading, sort of like electronic enrichment circuit. It's only my assumption, when firing up the bike it takes a couple of seconds to adjust it from 'base' idle rpm, I guess it's the time needed to get the sensors running and gradually increasing amount of fuel injected. Don't quote me on that, I can't think of any other way but it works.

It's only accurate with correct fuel map, synchronized tb and correct valve clearances. You can of course still do minor adjustements with air bleed screws as well like you said.

Quote from: pmazdan9 on February 26, 2020, 03:13:49 AM
Yes it's '05 s2r800 with cold start lever. I guess it adds more fuel until rpm sensor reading reaches value stored in the map depending on the air temp sensor reading, sort of like electronic enrichment circuit. It's only my assumption, when firing up the bike it takes a couple of seconds to adjust it from 'base' idle rpm, I guess it's the time needed to get the sensors running and gradually increasing amount of fuel injected. Don't quote me on that, I can't think of any other way but it works.

It's only accurate with correct fuel map, synchronized tb and correct valve clearances. You can of course still do minor adjustements with air bleed screws as well like you said.

AFAIK, there is an enrichment cycle on every startup that stays on until the engine reaches a set number of revolutions, I think it's until 1000 total revolutions.

Quote from: Speeddog on February 26, 2020, 08:07:07 AM
AFAIK, there is an enrichment cycle on every startup that stays on until the engine reaches a set number of revolutions, I think it's until 1000 total revolutions.

That would explain why it was set to 1000 in ECU by Ducati and confirms my theory I think.