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Discussion Starter #1
I notice when the bike is hot, especially in traffic, it will stall at idle. Also notice some coughing, maybe in the airbox, when opening the throttle a small amount at idle.

Also noticed short intake hoses in front of fairing pointing toward airbox opening...but can't possibly reach. Previously I assumed that was for some emissions requirement needed somewhere, but not here (NY/USA.) This may be moot.

I will change the plugs tomorrow. This is my first injected bike, so I'm a little lost. Idle is between 1000-1200. Runs great when rolling, though gets rough response at low RPM/slow-speed with small throttle openings. (I am fairly sure this is the nature of the bike.)
 

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i can't say for the st4 branch but a plug change on my new to me 98 st2 made a huge difference. stalling till reaching full op temp, then not much power off the line. i went with the iridium plugs, ran much better with the new plugs, i even went back from a 14t front sprocket to a the oem 15.
 

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Mr Leakered
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I had a self-induced cough issue due to the throttle body setup when sync'ing them the first time. I didn't fully diconnect the vert TB and started with an appearent bad reading for fully closed. The next time around, I set the TBs right and the cough is gone (no more puckers just off idle. So nice). You can make it cough stall when syncing your TBs if you turn the thumb screw too far the wrong way. Pretty neat.

Also, considering your's is a '99, your plug wires are probably toast, and new plug wires can make a big difference. Prior to properly sync'ing the TBs, the new plug wires smoothed out the stall somewhat and added 3mpg to 4mpg. Pretty freakin' cool. I used the 8.5mm MSD set fabbed by TPO Parts. Others had good luck with the Magnecor set obtained directly from Magnecor.

When changing plugs stay with the recommended Champion or NGK part numbers. I know it sounds odd, but I've even seen it on some cars where it will run the best with a certain NGK part number (plain old copper). Others have noted good to great results with the recommended Irdium alternatives.

Have a good one.
 

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Discussion Starter #5
Thank you Willum, Tonered and Dr1445.

Can anyone point to a thread on syncing throttle bodies? I've been reading what I find...seems I could do it with a multi-meter; but I know little else.
 

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I had the same issues with stalling when hot in traffic and the coughing issue. They both went away after I had the throttle bodies sync'd.
Yup, and while your at it, zero the TPS and finish up by fine-tuning the fuel trim.

Even if they come perfectly setup from the factory they tend to change a bit in the early days because the throttle linkages, TPS, etc. are all new and will bed in. Also, as your cylinders tighten up and the valves begin to seal better the engine will breath a little more air. It is necessary to add a touch more fuel to compensate.

I've heard it said that these engines don't smooth out until 10,000 or so miles but what is really going on is the engine is constantly running slightly leaner and leaner as it breathes better and better and also the throttle bodies are slightly out of synch as the linkages and butterflies bed in. Because it's all connected to the TPS, it is often necessary to adjust that as well. You can tune them up at any time and they will be smooth as silk right from the get-go but until they have 3000-8000 miles on them the state of tune will gradually creep. If it creeps too far you can experience the coughing mentioned. After 3000-8000 miles they are very stable for tens of thousands of miles at a time.

The transmission does become smoother shifting over a longer time period. I don't think my first ST reached optimum shifting for 25,000 miles. It shifted fine before that, it's just that it continually got slightly better and smoother as the miles were added.
 

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Mr Leakered
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Your best friends will be searching the Halls of Wisdom on this site or getting LT's manual from desmotimes.com. LT's manual has a step by step process for doing this including what pins to probe on the ecu.

While you're at it, visit duc.nu and download a shop manual for a few Euro. It's a poorly wrote manual that contains a ton of info and proceedures.

BTW, every time the valves are adjusted, the breathing is affected. So, the TBs should be sync'ed at least every 6k. It's relaxing after the shim surgery.

Also, your final fuel mixture will not be correctly set without a gastester ($225+). I've been living without one, but I'd surely like to check someday.

Good luck.
 

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Discussion Starter #8
Oh man.
Thanks, guys.
Well I found this procedure:
http://www.desmonorthwest.com/forums/showpost.php?p=107493&postcount=1
I think I might be able to get it done through adjusting the TPS, but not doing the balance. Actually, if I homebew rig-up a monometer as in that post, I might be able to do the throttle body balancing. But I have no other specialized tools at the moment.

Is this the right Desmo Times book?
"Ducati Desmoquattro Maintenance & Modification Guide - 3ed Edition"
Seems to cover a lot of bikes.
 

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....snip....

Is this the right Desmo Times book?
"Ducati Desmoquattro Maintenance & Modification Guide - 3ed Edition"
Seems to cover a lot of bikes.
Yes, that's the correct manual for your bike.
Bill W.
 

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i have read some opinions that state changes made to the valve adjustment can require a different tps setting. i have been trough the electrical connectors/plugs and wires, plus the spark plugs. my bike is coming up to the 6k mark so i have targeted a valve check, before chasing the tps, cyl balance etc. however, the bike now runs super and i am not chasing any issues. i am not sure where your bike stands on its routine maintenance status but you might want to check into that.
 

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Discussion Starter #12 (Edited)
Well, the bike only has about 2400 orig miles. First owner put about 600 mi on it. Then it sat unused for years. Second owner bought it slightly more than 2 years ago and did a service which included belts...I have that receipt, must locate it.

He took the mileage up to about 2k and sold it to me. Since the belts were 2 years old, even though the mileage on them amounted to nothing, I decided to change them.

Edit: I put a lot of miles on it Sunday, so actually I don't know what the odometer says right now. :)
 

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similar story with mine, less than 1k miles put on between 2003 and 2009. i got the bike with 4100 miles and a set of new belts under the seat so i did the belts right away. your 1st valve check isn't till 6k. the tps sounds like the way to go.
 

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Mr Leakered
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Honestly, your biggest challenge is getting tubes that thread into the intake and getting the wrench in there to snug them down. The rest is just following the steps. If you do it that way, I do believe you will be very happy.

The 'special tools' need to do bike maintanence is a bit crazy, but if you are obsessed, it's the only way to go. In the end, most of these tools can be used on serveral bikes.

I bought my ST with 20,800mi. It was almost pristine, so I don't regret it a bit. Although, I'm a bit envious of you guys finding those low mile examples.

Have fun.
 

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I needed some 6mm adapters for my 2005 ST3 since the MotionPro tool I bought only had the 5mm ones. I think I found them at a different site but these are the same thing.

5mm adapters

6mm adapters

Bill W.
 
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