2007 Monster S4RS Won't Idle

moto man · October 08, 2013, 03:27:21 PM

O.K. Here's my problem, 07 S4RS, 15,297 miles on it now, I can crank the bike, run it to temp (even 220 F) it will idle and run fine. I can even ride it, no problem. However, if I turn off the ignition (when hot, above 170 - 180 F), then crank it back up, it will not idle. Must give it throttle to keep it running. Let it cool to room temp, and it runs fine again.
I have checked: Battery, charging output, fuel pressure, spark plugs, coils, TPS setting, air & engine Temp sensors readings seem to be normal.
I'm stumped at the present time. Anybody seen this before/ got any ideas?
Thanks ahead of time.

Howie · October 08, 2013, 04:02:00 PM

Idle speed motor working correctly? How many turns on the air bleeds? Has anyone messed with the throttle stop screw?

Bill in OKC · October 09, 2013, 10:02:14 AM

I had a problem like that after I first got my DP ecu. I started playing with my trim values and at very rich settings (trying to stop some backfires) the bike did not like starting when hot. I posted about it and IIRC it was that the ecu goes through the enrichment cycle when first started no matter what temp the bike is. So I lowered the trim values and the issue disappeared. Did you change anything with the mixture recently?

moto man · October 09, 2013, 11:18:54 AM

The fuel tank was replaced recently, due to the "swelling" issue (ethanol fuel caused?). It also had a service at the dealer. I'm not sure what changes they made, but I'm going to try and find out.
I checked air bleeds, they are as follows: Horizontal Cyl = 1/4 turn out. Vertical Cyl = 1, 1/8 out.

Howie · October 09, 2013, 12:31:21 PM

Big difference between the two. The air bleeds should be used to equal CO at idle if needed. My concern would be why is the vertical 1&1/8 out. Attempt to synch with the air bleeds instead of the synch screw? Adjust to compensate for another problem?

I think the answer would be to go back to base settings and go from there, or, better yet, if this problem happened after that service bring it back to them.

moto man · October 16, 2013, 11:49:23 AM

Has anyone had or heard of an idle stepper motor malfunction? Any idea how to test one?

Howie · October 16, 2013, 09:08:22 PM

Yes, they can malfunction. Usually the symptom would be idle too high, too low or unable to idle. Though possible, in your situation I doubt it. Anyway, official Ducati test? Dunno. Shade tree? unplug it. Does it move? Plug it back in. Does it move?

Bill in OKC · October 16, 2013, 10:47:31 PM

Quote from: howie on October 16, 2013, 09:08:22 PM
unplug it. Does it move? Plug it back in. Does it move?

That would be a good test. I think it ~mostly~ is used to bump the idle on cold starts. Maybe also try unplugging it when the engine is warm? Mine was removed several years ago and it idles fine.

moto man · October 30, 2013, 12:08:10 PM

Howie, you state that the bypass screws should be used to equal CO at idle, however the Ducati manual states they are used to synchronize the throttle bodies. Can you elaborate? The official Ducati manual says nothing about setting CO values at all. Thanks.

JoeP · October 30, 2013, 01:54:12 PM

Quote from: moto man on October 30, 2013, 12:08:10 PM
Howie, you state that the bypass screws should be used to equal CO at idle, however the Ducati manual states they are used to synchronize the throttle bodies. Can you elaborate? The official Ducati manual says nothing about setting CO values at all. Thanks.

In my limited experience (I did this twice), you sync throttle bodies using the *sync screw* with both bypass screws all the way in. Then you back out both bypass screws by the same amount until you get a good idle. Measure the CO on both cylinders and see if they are close to spec. If not, adjust the fuel trim (I use Ducatidiag for this) so that one cylinder is where it needs to be (~4.5% for me). Then turn the bypass screw on the other cylinder so that the CO is the same.

My 749 had an idle problem (it would die at stop lights), but this fixed it.

moto man · October 30, 2013, 02:53:25 PM

I guess this S4RS is different from your 749. I have not found any "sync screw". Like I said the Ducati manual says the "bypass" screws are the sync screws. Am I missing something?

Speeddog · October 30, 2013, 04:26:54 PM

There is a rod that links the two throttle bodies together.

That's what you adjust to set the sync.

Howie · October 30, 2013, 07:29:41 PM

For whatever the reason the manual does say to synch with the bypass screws, but JoeP's method is better. You are correct, there is no synch screw. If you go to http://www.ducatiusa.com/services/maintenance/index.do and download the spare parts manual you will see the rod that Speeddog is talking about.

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2007 Monster S4RS Won't Idle