Ducati Monster Forum

Okay DMFers, I have a 2004 Monster S4R that's been giving me trouble lately and I could use your help. It is stock save for an Arrow 3/4 exhaust.

Back story: I purchased this bike in 2008. It required emissions testing first in 2009 and passed just fine with about 650 / 1500 ppm HC and around 2% CO.
The next year it passed again on the first try, but HC had jumped up to about 1300 (CO stayed around the same). I probably put 3,000 miles or thereabouts on it during this time.
When I went to do emissions this year (after only putting about 1,000 miles on the bike during the past year, argh!), I failed the first time with a HC reading about 300 ppm too high. With the help of a fellow Ducatisti buddy I did a tune-up (at 22k it was probably due anyway). I changed the oil with the same 20w50 I've always used and inspected the air filter (absolutely beautiful). I replaced the plugs with DCPR8Es and checked valves (all within spec, though a couple were on the tight end of the spectrum). Cam belts were replaced with direct-fit California Cycleworks units and tuned to 105Hz (+/- .5Hz). We also set the idle a bit higher, if memory serves.
Failed again. This time HC was way too high -- around 2,900ppm, I believe.

I took the Duc to my buddy's house, where we hooked it up to his VDST. He reset the TPS (which was off, but only by a very small amount) and we adjusted fuel trim based on seat-of-the-pants feel. Since the bike has always popped on decel, we aimed to reduce this since said popping is generally a sign of a lean fuel mixture and high hydrocarbon readings back this up. The fuel trim was set at +8; we settled on +50, as this resulted in the best rideability and feel; we turned down the idle screw to compensate for the richer mixture. There was also some fiddling with the air bleed screws.
Failed again. HC had come down to a couple hundred ppm over 1500, and CO had risen too (but was within spec).

This time we met up at a local shop (if anyone's in the Phoenix area, Eric at DP Motorsports is a lifesaver) where we hooked up the bike to an EGA sniffer and the VDST tool again. Bringing the fuel trim up higher just resulted in HC readings off the charts and increased CO too. Turns out the solution was to adjust the idle fuel trim back down to +15. I ran it through emissions and it passed (after stumbling and dying once at the test station with the idle too low). Cool. Bike is tagged again.

However, it's just not running right now. I reset the idle screw in a bit to compensate for the leaner idle mixture and it kinda sorta idles around 1200-1500. It likes to surge at idle, though, and stumbles a bit. At any throttle application the stumble goes away and the bike runs beautifully, but it's a pain in the butt that I can't get a consistent idle; worse is that it frequently dies at a stop or when I coast. Again, with any throttle application everything seems fine but in a closed-throttle condition it's all wonky. I can upload video of the bike/tach if that would help.

Does anyone have any ideas? I went through and ensured that I was getting spark (I am) and that the velocity stacks were correctly re-seated after installation so as to prevent air intake bleed (they weren't, but fixing that didn't ameliorate the problem at all). Vacuum lines are all where they should be. I'd much appreciate any thoughts or suggestions.

Thanks!

Synch throttles again, adjust air bleeds, re check synch.  The bike should run best at 4-6% CO and proper cylinder balance will give you the lowest HC level.  If 4% is too high for state inspection turn it down a notch for your next one.  Do keep in mind the shop's goal was to get you through inspection.  They were successful at that.  They might be willing to get the bike back to a setting that makes you happy.

The goal was of course to pass emissions (max value HC 1500, CO 5%). That worked. But what would cause the huge spike in HC over the past two years? The bike used to run fine AND pass emissions, so it seems to me that something must have changed over the past 3,000-4,000 miles. I also would like to be able to do this myself, but if I have to admit defeat I will!

run a bit of  seafoam thru it to clean out the innards before you smog it.

What were the valve clearances?

Why did you put DCPR8E's in?

Valve clearances are as follows (in crap-ass form because I can't get good table formatting to work):

Horizontal cylinder valves      (Control values)      
     Intake       Exhaust   
   L   R    L    R
Openers   0.11 (.05-.18)   0.11  (.05-.18)   0.2 (.05-.23)   0.2 (.05-.23)
Closers   0.2 (.13-.25)   0.22 (.13-.25)   0.16 (.08-.20)   0.12 (.08-.20)
            
            
Vertical cylinder valves            
   Intake      Exhaust   
   L   R   L    R
Openers   0.13  (.05-.18)   0.13  (.05-.18)   0.22 (.05-.23)   0.21 (.05-.23)
Closers   0.22 (.13-.25)   0.23 (.13-.25)   0.18 (.08-.20)   0.18 (.08-.20)


I put in DCPR8E plugs (at .6mm gap, torqued to 21 lb./ft.) because it was roughly at the interval and I was already in there doing work anyway.

Air bleed screws are both set to 3/4 turns out. Idle is high because at first I thought a low idle was causing my problem. Now it just surges and stalls with a higher idle speed.

The video shows the tach while the bike is running; you can see/hear what's going on. It didn't do this before all the work to get it to pass emissions. I'm still concerned about the jump in emissions output from one year to the next, given the relatively few miles that were put on it in that time. EEL, I did indeed run some Seafoam through the bike.

VID 00035 20110317 1236 (http://www.youtube.com/watch?v=D5ygXRDgL88#normal)

Thanks for the help, folks!

Wouldn't bad piston rings increase HC?

I thought about it maybe being the rings, but I'm not seeing white smoke or any other such signs. Oil consumption is essentially negligible. I top it off less than I do my Hayabusa, which never has a problem with emissions.

That said, though, that still doesn't account for the sudden rough idle.

Some more back story: The first time I went to my buddy's house, we set the fuel trim rather high (+55) and the idle screw low and the bike ran great but failed smog. Ultimately we went to a shop and put the bike on an EGA. We opened the air bleeds a bit and dropped the fuel trim to +15 (it was originally +8). The bike passed emissions but has been idling poorly since that day. In fact, it stalled out during the idle test at the emissions station.

Could be the rings, but that is a little like leaping to the conclusion that someone has a brain tumor because he has a headache.  Re check TPS, synch and cylinder CO balance.  If you have an EGA the best way to balance CO is to pull the plugs in the manifolds so you can get individual CO readings for each cylinder.  Instead of backing the air bleeds out individually, balance the CO with the air bleeds.  Before doing any thing make sure you have no vacuum leaks.

The TPS was zeroed at the shop, but I'll re-check the voltage there. I should probably just get some carb sticks to do the synch myself; I've been calling on that abovementioned buddy too much.

I'll also go through and check for vac leaks again, but it came on so suddenly when I wasn't futzing with hoses that seems weird. Still, though, I'm obviously pretty stumped! :)

It doesn't seem like a vacuum leak. At least, I haven't been able to find any worn / loose hoses.

Update:

Still no sign of a vacuum leak. With the help of a good buddy and Ducati nut, we went through and made sure all air bleeds were capped and such. We did find a couple uncapped points and two exhaust leaks; we capped the bits that needed it, and used high-temp sealant on the exhaust joints to eliminate the leaks.

And yet, still no luck.

I took it to an actual mechanic today (oh, how it shames and hurts me to do that!). He was fairly stymied and suggested that I check the compression and, if compression checks out, the fuel injectors. He thought that perhaps the front fuel injector was faulty or clogged, as it sounded to him as if the front cylinder had a lean miss.

Since I didn't have time today to tear the bike down to the throttle bodies, I thought I'd do a compression test. I followed procedures according to the Ducati service manual. With coils removed, the tester screwed into one cylinder and throttle WFO, cranking yields 179psi rear and 171psi front. The manual calls for 11-12bar, which translates to roughly 160-175psi. I'm guessing a +.4b rear compression isn't causing my problems.

So now I suppose I wait for the time to get down to the injectors unless anyone else has suggestions!

http://www.mrinjector.us/index.html (http://www.mrinjector.us/index.html)

injectors cleaned, rebuilt, & flow tested for $16 a pop

good cheap way to potentially eliminate a problem without buying new injectors, or bad used ones

I just found this on mine, which was also not running or idling properly..

(http://farm3.static.flickr.com/2228/5717569440_8ed62bf93a_z.jpg) (http://www.flickr.com/photos/62789714@N05/5717569440/)
hole in vacuum hose (http://www.flickr.com/photos/62789714@N05/5717569440/#) by Ducmonster696 (http://www.flickr.com/people/62789714@N05/), on Flickr

Have you considered the possibility of an electrical problem, perhaps a grounding issue?

Also isn't 3/4 turn out on the air bleeds a little too rich? I have a different bike I know, but the air bleeds on it are out 3 full turns, for an idle of ~1250.

Well, still no luck. I had the fuel injectors cleaned and flow tested. Both passed (rats). Plugged 'em back in, and the bike still idles poorly. For the life of me I just cannot see any vac leaks, though that's what it sounds like I have.

At least compression is good (179/171 f/r).

It might just be time to haul it into a shop. I've been trying for almost five months to fix this problem and it has just eluded me time after time.

Propane and propane accessories. . .

Monster S4R idling poorly: Propane and propane accessories (http://www.youtube.com/watch?v=gPZvWkEf5EA#normal)

Looks like there's a vac leak at the front butterfly vane.

. . . how on earth do I fix this?

First put the ECU trim back to 10 or less

second Zero the TPS correctly

third Sync the throttle bodys at 3K RPM

fourth, set the CO at idle by using the bleed screws- set level to 2.0-2.75 or maybe a little less for your inspection.  should be 4-6 for best performance,

If the HC level is high at this point do a leakdown test

My guess off the bat is that a valve is leaking, either through out of spec or through a valve guide.

It failed emissions at +8 and passed at +15 but hasn't idled correctly.

TPS has been zeroed very recently, and throttle bodies have been synchronized well. Bleed screws have been similarly set.

Valves have been examined, and all are within spec.

I could do a leakdown test, sure, but it really seems like I've hit on something when the idle smooths out so dramatically when there's propane introduced near the front cylinder (and there only).

You only proved that cylinder is running lean by that test.  Could be a vacuum leak, could be a fuel problem (like a bad injector).  Put a smaller, more flexible hose on that propane torch so you can target different areas like intake runner gaskets and throttle bodies.  Keep in mind some leakage at the throttle shafts is normal.  Or you could go to an automotive shop with a smoke machine and ask them to hook it up.

Can do. I know the injectors are good, though; they were cleaned and flow-tested just last week, and both passed quite well. Since the problem is with the front cylinder, I swapped the injectors F-R to see if the problem would change; it didn't, which leads me to believe it's not an injector issue.

I'll do some more work with the hose today.

I work in inches, so, converted:

Horizontal cylinder valves         
             Intake       Exhaust   
             L     R     L      R
Openers   .004   .004   .008  .008
Closers   .008   .009   .006   .005
            
            
Vertical cylinder valves            
             Intake       Exhaust   
             L     R     L      R
Openers   .005   .005   .009   .008
Closers   .009   .009   .007   .007

I don't have my database at hand, but IIRC, those clearances don't look good.

According to the shop manual, all valves are within control tolerances (in the original chart, the values in parentheses).

Yes.  ;)

For reference, S4 service manual says:

Intake openers: 0.10-0.15, limit of 0.05 (.004"-.006", limit .002")
Exhaust openers: 0.15 -0.20, limit of 0.05 (.006"-.008", limit .002")

Closers: 0.05-0.10, limit of 0.20 (.002"-.004", limit .008")
-------------------------------------------------------------------

I'd go for within the ranges, so IO 0.10-0.15, EO 0.15-0.20, and Closers 0.05-0.10

In general, Ducs don't run well at idle and part throttle with loose closers.

Are you looking at the S4 (916) manual or the S4R (996) manual? From the S4R service manual:

Opener specs:
Intake:
Nominal: .20
In Operation: .18-.23
Check: .05-.18

Exhaust:
Nominal: .20
In Operation: .13-.18
Check: .05-.23

Closers:
Intake:
Nominal: .15
In Operation: .13-.18
Check: .13-.25

Exhaust:
Nominal: .15
In Operation: .08-.13
Check: .08-.20

Here's some info from LT Synder's Ducati Desmoquattro Maintenance and Modification Guide, 3rd Edition:

Ducati 4-valve Recommended Clearances (pre-tesastretta)

Recommended:

Intake:
Openers: .002"-.007" (.05-.18mm)
Closers: .006"-.010" (.15-.25mm)

Exhaust:
Openers: .002"-.009" (.05-.23mm)
Closers: .004"-.008" (.10-.20mm)


I sure hope I don't need to get in there again and adjust valves. That's a SERIOUS pain in the butt. Besides, that also doesn't explain the "sucking" noise on the front cylinder or the flash riding up the throttle body as shown in the video.

Clarifying the LT Snyder table, he has a column on the right "My Setting":

Ducati Recommended                                            My Setting

Intake:
Openers: .002"-.007" (.05-.18mm)                          .004" (.1mm)
Closers: .006"-.010" (.15-.25mm)                           .004" (.1mm)

Exhaust:
Openers: .002"-.009" (.05-.23mm)                          .006" (.15mm)
Closers: .004"-.008" (.10-.20mm)                            .004" (.1mm)

I'm fully aware of how much work it is to do 4V clearances.  ;)

The problem may exist elsewhere, but there's baselines that have to be correct so you can eliminate them as suspects.

While it would be nice to have every valve spot-on, that's just not feasible right now. While I could see tolerances that are too tight/too loose being problematic with stumbling idle or whatnot, that wouldn't explain the flash up the throttle body and it also wouldn't explain the "tsst tsst tsst" sound either.

With none of the valves out of official Ducati spec, I just have a hard time believing that would be a factor that would have to be eliminated right away.
. . . In large part, because JESUS, Ducati, could valve work be any more difficult?

Ditto,

and from the video what you are experiencing is called a lean sneeze and it is from the TPS not being set correctly, and the throttle bodies being out of sync/carbon around the plates.

I have an 05 and had this problem. 

How did you guys reset the TPS on this bike? (detailed please)

Yep, turns out that it's the TPS. The TPS had been reset using the Ducati VDST and that didn't report a problem. However, a test with a custom harness extension, a multimeter and a screwdriver showed me today that the TPS was reporting erratic voltages at small throttle openings: It was internally consistent with the throttle shaft, though, so was fooling the scan tool. I cleaned the Weber PF09 unit as well as possible and reinstalled it.

Lo and behold, now the bike runs great! It's not sputtering or popping at all, even on closed-throttle deceleration.

On the other hand, based on a quick EGA test, it's running very fat. Well, an EGA test and the smell -- it's DEFINITELY running rich. But at least it's running! I'm out of the country for a couple weeks starting tomorrow; when I get back I'll probably replace the TPS and will definitely have to re-balance the throttle bodies and tune the bike.

And now I'd like to buy another TPS because I don't know that I trust this one. Looks like it was used in a number of Ducatis as well as Cagivas and even Ford cars. Hopefully I'll find one that's affordable!