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Discussion Starter · #1 ·
Tried to search this forum, but couldn't find anything on "blow-by"...which makes me think I didn't look hard enough. If not, please direct me. Thanks! So....

Iv'e got an 07' 1098 that I've owned for the last 2 years. It's in fair-good shape...been wanting to sell it, but apparently this is not a great market for a 18k, rebuilt title, ten year old bike. So I decided to just keep it. #1 of 6...so my trim-down plan isn't working. Anyway, took it to a nearby Ducati dealer to get the Desmo done and few other things and received some bad news. "You've got major blow-by going on", is what I was told. That means that the much irritating STALLING issue that makes riding this thing sad, probably isn't going to be fixed even if I went ahead with the Desmo. I'm pretty sure that's what they were saying, or what was agreed upon. So I'm supposed to pick it up and "enjoy it as is". Also: I mentioned doing a compression test and they seemed to think there was no point. Thing rides like a beast, by the way.

Questions:
1.Does anyone have any info on how this impacts the stalling issue?
2. Is there a way to test it myself to make sure the dealership didn't misdiagnose the problem?
4. How much blow-by is normal?
3. If I disclose the stalling...is it lame to try to sell it anyway?

Any info is greatly appreciated. Thanks
 

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Your stalling issue isn't related to blow-by — and unless you're experiencing excessive oil consumption, the amount of blow-by is probably within normal limits.

Piston rings act as a seal between the high pressure created in an engine’s combustion chamber and the lower pressure in the crankcase. Blow-by occurs as the rings become worn — or fail to seal properly when new – and they allow a small fraction of combustion gases to leak into the crankcase.

The consequences are accelerated contamination of the engine oil, as well as excessive release of hydrocarbons to the atmosphere, unless a crankcase ventilation system is used to route the gases back to the engine intake to be burned.

On Ducati engines, excessive blow-by can cause unusually large amounts of entrained engine oil to be forced through the crankcase ventilation system and into the airbox. It’s not unusual, however, to occasionally see a light deposit of oil in a Ducati airbox.

Blow-by occurs in all engines to varying degrees as they wear, but when it becomes excessive, an engine rebuild with new piston rings is in order.
 

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I was getting a bit of blow-by on my 1198, then one day I found oil dripping from the airbox. I pulled everything off and there was oil 1/4 deep in the airbox. This is pretty common especially in hot weather on the track as oil vapor pushes past the vent reeds and collects in the airbox. still i decided to replace the stock crankcase vent with a PSR one, which helped but i was still getting lots of oil misting in the airbox

I routed my crankcase vent up into the tail and put a filter on it. I machined an in line baffle setup and pressed it into the hose above the reed crankcase vent because I was still having some leakage from the filter. The only time it leaks now is when you ride wheelies for too long. I have been meaning to re-route it and put it up in the front where the EVAP can used to be, but there is not a lot of room to run the hose forward.

I think the complete fix would be to run the hose forward to a sealed catch can and then run another hose back to the exhaust and use a vibrant vacuum fitting to pull negative pressure on the crankcase, that way your not losing power on the top end, and keeping the air moving. I have had lots of success with these on high HP subaru builds.

Vibrant Performance ::.

I think this has little to do with your stalling issues though. That's probably too much fuel, the 1098-1198 are known for having terrible fuel mapping from the factory.
 

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Discussion Starter · #4 · (Edited)
Your stalling issue isn't related to blow-by – and unless you're experiencing excessive oil consumption, the amount of blow-by is probably within normal limits.

Piston rings act as a seal between the high pressure created in an engine’s combustion chamber and the lower pressure in the crankcase. Blow-by occurs as the rings become worn – or fail to seal properly when new — and they allow a small fraction of combustion gases to leak into the crankcase.

The consequences are accelerated contamination of the engine oil, as well as excessive release of hydrocarbons to the atmosphere, unless a crankcase ventilation system is used to route the gases back to the engine intake to be burned.

On Ducati engines, excessive blow-by can cause unusually large amounts of entrained engine oil to be forced through the crankcase ventilation system and into the airbox. It’s not unusual, however, to occasionally see a light deposit of oil in a Ducati airbox.

Blow-by occurs in all engines to varying degrees as they wear, but when it becomes excessive, an engine rebuild with new piston rings is in order.
Thanks Shazaam! Your explanation of things is very much in line with what I thought(a.k.a able to research). Begs the question then...why did the dealership turn down a $1300 Desmo? Bike was in their shop, fairings off ready for new belts, etc. and they called to tell me that it probably wouldn't solve the stalling issue because of the "major blow-by". I appreciate them trying to save me $$ for a repair that wouldn't have solved the main problem that I brought it to them for...but now I'm left wondering if I should get a second opinion.

Oddly, when I asked them how they knew that there was so much blow-by...their explanation was vague at best. No mention of oil being in the airbox, at all. Would a leak down test remove some of the mystery here?

Call me paranoid, but I'm concerned about "forcing" a dealership to be more specific and detailed about a diagnosis that they've already made and...doesn't necessarily make any sense. Put them on the defensive while they've still got my bike hostage..?? Ha! I suppose I'll call again today, in spite of my deep, deep paranoia regarding dealerships. After all they seem like really cool guys(in case they're listening!!).
 

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Would a leak down test remove some of the mystery here?
Yes. An engine in great condition should generally show only 5 to 10% leakage. An engine that's still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.

In particular, if during the test you can hear air coming out of the PCV system outlet to the airbox, this would tell you the rings and/or cylinders are worn and confirm a excessive blow-by diagnosis if the leak-down rate is high.

Of course. a leak-down test isn't definitive. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve.
 

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Discussion Starter · #6 · (Edited)
Yes. An engine in great condition should generally show only 5 to 10% leakage. An engine that's still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.
Again...thanks for the fantastic information Shazaam!

Thought I'd follow up here. Got the bike back, and the Desmo was NOT done. They did do a leak down test and said..."The readings my tech had found on the leak-down test were 12% on the horizontal (front) cylinder and 24% on the vertical (rear) cylinder." They reset the TPS as well.

So...the bike still stalls once it gets up past 200 degrees F. In fact, it stalled no less than 7 times on the short 10 mile trip back to my garage. It kind of makes me feel like the bike is useless, especially in the city(Chicago). Thing is, it's still ridiculously powerful. Wouldn't feel right to put it out to pasture, nor would I be able to get a reasonable price for it if I'm absolutely forthright about what's happening and why. You look at it, you hear it...let alone ride it, and it doesn't seem like a $5k bike. But who'd even pay that for a stall-o-cycle? Just venting a bit...please excuse, and thanks again for the help.
 

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On another note, your $1300 service would be included in the rebuild/blueprint service that you may get if you do decide to get the whole engine done up. Hopefully you don't go that route as it is around $4-5k, but it does help account for a good chunk of change. :)
 

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Desmo = The services recommended by Ducati at different mileage intervals. Done by a certified Ducati tech, I suppose.

At least that's what a lot of people call it, eh?
Desmo refers to the desmodromic valve system Ducati uses. The services are just services.
 

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Tried to search this forum, but couldn't find anything on "blow-by"...which makes me think I didn't look hard enough. If not, please direct me. Thanks! So....

Iv'e got an 07' 1098 that I've owned for the last 2 years. It's in fair-good shape...been wanting to sell it, but apparently this is not a great market for a 18k, rebuilt title, ten year old bike. So I decided to just keep it. #1 of 6...so my trim-down plan isn't working. Anyway, took it to a nearby Ducati dealer to get the Desmo done and few other things and received some bad news. "You've got major blow-by going on", is what I was told. That means that the much irritating STALLING issue that makes riding this thing sad, probably isn't going to be fixed even if I went ahead with the Desmo. I'm pretty sure that's what they were saying, or what was agreed upon. So I'm supposed to pick it up and "enjoy it as is". Also: I mentioned doing a compression test and they seemed to think there was no point. Thing rides like a beast, by the way.

Questions:
1.Does anyone have any info on how this impacts the stalling issue?
2. Is there a way to test it myself to make sure the dealership didn't misdiagnose the problem?
4. How much blow-by is normal?
3. If I disclose the stalling...is it lame to try to sell it anyway?

Any info is greatly appreciated. Thanks
I suspect your stalling has nothing to do with blow by (as Shazaam said). Have a search for stalling and look for '07 1098. I believe that some early motors had the wrong cams (valve timing off) or something like that. Also get your ECU reflashed.
Leak-down doesn't necessarily mean blow-by from worn rings. If the valves aren't seating properly, you will get leaking past them. Maybe you have some tight valve openers or loose closers?
Find another mechanic to look at it.
 

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Discussion Starter · #14 · (Edited)
So this happens at 200F... Does it also happen at certain RPM intervals? Do you have a QS or aftermarket ECU/power commander installed?
Yes, 200 degrees and above...never below. I've got Termi slipon's and the race ECU for it.

"RPM intervals"? It almost always happens while idling sitting at 1300 at a light. If I'm at a stop light for a minute...it'll happen 15-30 seconds in.
 

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Leak-down doesn't necessarily mean blow-by from worn rings. If the valves aren't seating properly, you will get leaking past them. Maybe you have some tight valve openers or loose closers?
Find another mechanic to look at it.
If the valves haven't been adjusted properly this can also cause stalling when idling — just one valve can do it.

Other causes relate to fuel/air ratio problems such as small air leaks that are significant at idle small throttle openings but don't affect operation at higher engine speeds. CO level readings at idle from an exhaust gas analyzer will give you a clue.

Perhaps a bad lambda sensor. The bike uses the sensor to run the fueling closed loop when the engine is up to temperature but only at lower throttle openings.
 

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Discussion Starter · #16 ·
I believe that some early motors had the wrong cams (valve timing off) or something like that. Also get your ECU reflashed....Find another mechanic to look at it.
"Find another mechanic...". Seems so simple, doesn't it? Mechanics around here won't even talk to you about anything "detailed" like that. Not on a bike this old, anyway. Can't speak to newer bikes. I drove quite a ways out of town to find a mechanic that I'd trust at all. I found this "fix" below for the stall on another forum, and it seems like it makes some sense, but trying to get a Ducati mechanic to actually do it...well...it seems very unlikely.

This is the remedy posted elsewhere:

"I have the slip ons with the racing (correct factory supplied, not stock) ECU.

1) Make sure the cables on the exhaust valve are connected correctly. Aparently a few bikes have had them reversed. With the slip ons and the slip on ECU it doesn't matter since the valve is always open.

2) Battery voltage and Amperage within spec.

3)Cylinder balance within spec.

4)Reset TPS.

5)Adjust trim to plus 15.

6)Adjust air bleed screws to 3.5% CO."

Seems like I would be able to hire a mechanic for 2 hours and get this exact thing done.
 

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If the valves haven't been adjusted properly this can also cause stalling when idling — just one valve can do it.



Other causes relate to fuel/air ratio problems such as small air leaks that are significant at idle small throttle openings but don't affect operation at higher engine speeds. CO level readings at idle from an exhaust gas analyzer will give you a clue.



Perhaps a bad lambda sensor. The bike uses the sensor to run the fueling closed loop when the engine is up to temperature but only at lower throttle openings.


This seems to be the right track. It's really the only reason I was asking for the certain interval or range of rpm. I've heard of people having certain engine cutout issues at 2k or 4K or other random numbers. It's just a shot in the dark, it's usually something to do with mapping or the PC if installed as the OP doesn't. OP I think shazaam has got you an idea, I would give a call to a competent dealer if some sort. I can't remember where your location is, but I'm sure we can point you in the right way if you check your sensors and other tolerances as mentioned and they aren't the problem as a easy fix.
 

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Discussion Starter · #19 · (Edited)
So, a quick update. Started looking into things myself and so far I've found a few problems. The first thing that I noticed was that the airbox was not attached to the vertical intake properly. Not positive that it was a leak, but it looked possible...the clamp was bent and not fully down around the rubber. Secondly, the airbox was as dirty as anything I've ever seen. Basically full of sand and grime. Didn't see any oil, but perhaps that's what the sand and dust was sticking to..? Clearly something was not right as it should have been completely clean, I would think. Looking down the air intake? that goes to the valves I could see some dirt and grime build up, but nothing totally out of the ordinary(compared to pics from the web).

I really got the feeling that the dealership didn't actually do a leak down test, or check the filter like they said they did. Is it possible they changed the oil, listed the above and charged me almost $300?

I'll do compressions test...cold, hot, and then with a bit of oil. Something tells me that the sand and grime may have ruined the rings and caused blow by...if blow by was even the issue. Anyway, it's a start. If the horizontal cylinder is lame, then I guess I've got to replace the pistons and the cylinder? That, or buy another engine. Anyone got a good one to sell?

Kind of an odd question, given the forum but - are these bikes worth the trouble? I went into the engine of my KTM 990 Super Duke when, according to the KTM dealer, the engine was "seized" up. Didn't take long for me to find out that it was a collar bolt inside that had worked its way out against the crankshaft. $11 part and some new gaskets and it's been a blast roaring around town ever since. Honestly, I enjoyed doing the work. Picked up that bike for a song and a dance...the 1098, not so much. Anyway, I'd be curious if the people that STILL 1098's are stoked about it...or are they looking at the Panigale's and feeling like a change? Heck, this bike has never given me the warm fuzzies I had gotten from my 749S, but perhaps that was because it was my first Ducati...and it wasn't such a beast. I could part this bike out, but it seems like it'd be a shame. So would forking over a few grand$$ to get it back in shape! I suppose confusion of this sort is normal when faced with potential serious issues on an "older" bike.

Thanks for the help and suggestions!
 

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I suspect your stalling has nothing to do with blow by (as Shazaam said). Have a search for stalling and look for '07 1098. I believe that some early motors had the wrong cams (valve timing off) or something like that. Also get your ECU reflashed.
Leak-down doesn't necessarily mean blow-by from worn rings. If the valves aren't seating properly, you will get leaking past them. Maybe you have some tight valve openers or loose closers?
Find another mechanic to look at it.
Could you elaborate on the leak down issue and the valves? I'm trying to isolate my issue as well, and did not consider the valves. Do you imply that a valve service would alleviate the problem, or do you mean the cam rocker arms need replacement?
 
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