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Discussion Starter #1
Hey Guys,

I was on track today, at the very end of my last session I grabbed an upshift, and all of the sudden very little power. I checked the gauges and the oil light was on. Immediately pulled off track and hit the kill switch. Checked for a trail of oil, nothing, not even a leak.

When I got back into the paddock I pulled the fairing off, no oil leaking, oil level is good and oil quality looks great.

Quick googling points to the oil pressure switch failure, but I don't see anything about loss of power in those threads. The bike has an open clutch cover(so it's already loud), but I did not hear any odd sounds from the engine.

Does anybody have any insight they could share? Thanks!
 

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It's not unusual for an engine to stall due to something else, such as fuel starvation, and then the rider pulls the clutch and then sees the oil light, which is of course on because the engine quit turning when he pulled the clutch lever so it is not creating oil pressure. The low pressure oil light is dong it's job at that point but not indicating a problem
 

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Did the engine feel rough or knock?

Have you restarted to see what it does?
 

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Discussion Starter #4
It's not unusual for an engine to stall due to something else, such as fuel starvation, and then the rider pulls the clutch and then sees the oil light, which is of course on because the engine quit turning when he pulled the clutch lever so it is not creating oil pressure. The low pressure oil light is dong it's job at that point but not indicating a problem
Very valid point, one that I didn't consider since I had just fueled up and the light came back on when I restarted the bike a few minutes later.


Did the engine feel rough or knock?

Have you restarted to see what it does?
I have restarted it, a few minutes after I got into the pits. Did not hear any odd noise, but the open clutch cover could be masking a sound I suppose, but I think a knocking rod would be loud enough to hear over it?

I then restarted the bike when I got home and the engine was cold. I only let it run for a few seconds, but the oil light went out when I started it up. That makes me think maybe it's not a rod bearing? I would think that would mean the oil light would be on, regardless if the oil is cold, but I am just speculating.
 

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With a properly spun bearing you will hear the knock over the clutch. The engine will also lack in power but feel like lit is misfiring hard. No like a normal misfire.

For starters, you are going to check the oil pressure, and if you do not have a gauge for it, then replace the old sending unit with a new one. Ride/run it, then go from there.
 

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Discussion Starter #6
With a properly spun bearing you will hear the knock over the clutch. The engine will also lack in power but feel like lit is misfiring hard. No like a normal misfire.

For starters, you are going to check the oil pressure, and if you do not have a gauge for it, then replace the old sending unit with a new one. Ride/run it, then go from there.
Thanks, I will do that. I rode it for maybe 5 seconds after realizing I had no power, and did not ride it again. Going to replace that sensor today and report back. If there is still no power I'm going to drain the oil and check the screen for debris.

I appreciate the help! I am very mechanically inclined but have never cracked a desmo motor open, so fingers crossed that is a skill I don't need to learn right now..
 

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You could also pull the clutch pack out to eliminate that noise just in case it is masking something else.
 
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Discussion Starter #8
Ok, update:

Replaced the oil pressure sensor, no problems there, oil light goes off seconds after startup.

Start riding the bike, and after 3k there is a loud knocking. I kept then revs low and brought it right back to the garage and drained the oil. Lots of metallic flakes in the oil and on the drain plug.

What are my next steps? Drop the motor, and..?
 

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Sounds like you lunched a rod bearing. Bummer. Cases gotta come apart for that. Don't turn it over anymore and the crank might be salvageable. Just gotta dig in there and see. Good luck.
 
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Sounds like you lunched a rod bearing. Bummer. Cases gotta come apart for that. Don't turn it over anymore and the crank might be salvageable. Just gotta dig in there and see. Good luck.
I wasn't ready to tell him that. You are so brave.
 

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My condolences. Running a session on a track will heat soak a motor to an extent that street riding will never do, especially with high ambient temperatures. Proper oil coolers and monitoring are essential.

I have a feeling from your writing style that you would be able to manage an overhaul without being that challenged but sometime a replacement engine is a better option because their are so many of them available from crashed bikes. When you potentially have a damaged crankshaft, and metal throughout the motor, the process is exacerbated. Some people chose to get going with another engine and then tackle the original over time to see if it is worth the parts and time. Sometimes, you can end up with a set of heads that you can play with.

There are so many Suzuki GSX's crashed that many times there are $500 complete low time engines around. Ducati, perhaps not so many but I still see a lot of them.
 

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Discussion Starter #12 (Edited)
I wasn't ready to tell him that. You are so brave.
:smile2: I was just crossing my fingers it wasn't, but I had a gut feeling that it was a rod bearing.

My condolences. Running a session on a track will heat soak a motor to an extent that street riding will never do, especially with high ambient temperatures. Proper oil coolers and monitoring are essential.

I have a feeling from your writing style that you would be able to manage an overhaul without being that challenged but sometime a replacement engine is a better option because their are so many of them available from crashed bikes. When you potentially have a damaged crankshaft, and metal throughout the motor, the process is exacerbated. Some people chose to get going with another engine and then tackle the original over time to see if it is worth the parts and time. Sometimes, you can end up with a set of heads that you can play with.

There are so many Suzuki GSX's crashed that many times there are $500 complete low time engines around. Ducati, perhaps not so many but I still see a lot of them.

This bike is a track-only bike. It was my 7th day on it and it was on oil that had 2 days on it. It wasn't particularly hot but Auto Club has a very long straight and you spend a lot of times in high-revs.


I also think I can manage an overhaul, I'm just a bit timid about certain bits, like the impossibly(seemingly) precise tolerances. I have the tools I know, it's just things like setting squish and backlash that scare me. I would hate to get it put back together just to have it explode again. But I do have the time and tools and motivation(I think..).

Also, does the fact that it idles absolutely fine indicate that the bearing(s) might not be so catastrophically destroyed that main bearings won't need to be replaced? What is the best- and worst-case scenario once the engine is cracked open? Looking through the service manual it sounds like the heads need to come off to crack the case open, it's pretty much as intensive of an engine job as possible. Time to do LOTS of research..

Also, do you know if it is possible to pull the heads off without touching the timing/removing valves? Forgive me if that is a silly question but I haven't pulled a Desmo head off before.
 

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You can pull the heads off without having to touch the valves. So that's not gonna be a problem. I haven't changed belts myself before, so I don't know about the cam timing. I think you can 'lock' the cams in the right position when changing belts, so that could also be a non problem (does require a specific tool I think).

There should be plenty of smart people who can fill you in on the cam timing part.


Edited:
I just looked at some videos bout replacing cam belts. I think it's important that before removing the belts you check the markings on the rollers (the one at the crank and the 4 cam rollers) to check if they are where they should be. If so than you can easily time the cams like they were.


Jacco
 

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mains are roller bearings. only plain bearings in it are the big ends. worth reshimming the crank anyway, you'll reduce the loading i would expect. they're pretty simple motors.
 

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If it is the big end bearings and the crank is fine, replacing the bearings is not too difficult. Whether you replace the engine or attempt the necessary work on your current one, the engine is coming out. That's out of the way.

If you don't reshim the crank, as in keep it just like it is, and only want to replace the bearings, lay the engine on the clutch side, disassemble to the point of allowing the left 1/2 of the case to come off, replace bearings, bolt everything up in he reverse order at it was taken apart. But, a 748 engine can be found fora few hundred $'s.

Like bradblack states, they are simple engines.
 

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Discussion Starter #17
If it is the big end bearings and the crank is fine, replacing the bearings is not too difficult. Whether you replace the engine or attempt the necessary work on your current one, the engine is coming out. That's out of the way.

If you don't reshim the crank, as in keep it just like it is, and only want to replace the bearings, lay the engine on the clutch side, disassemble to the point of allowing the left 1/2 of the case to come off, replace bearings, bolt everything up in he reverse order at it was taken apart. But, a 748 engine can be found fora few hundred $'s.

Like bradblack states, they are simple engines.

Thanks for the info, everybody.

Is there a reason that I should re-shim the crank? What advantage comes from doing that vs. not? Some quick googling and ebaying has found 748 motors for about $1,000 plus. If i'm going to do the work myself, it sounds like I might be able to get away with ~$500 in parts? I know I need new big end bearings, and assuming I should get the crankcase gasket kit as well? What else would you guys replace while you're in there?
 

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I've done timing belts and valve adjustments on my 996, but am not an expert on bearings. I think I'd go in the following order... based on hearing of the particles you are getting.

1. check timing belts and timing - did a belt jump a tooth?
2. Pull the motor out and drop the pan. Clean all the passageways and residue out. Do the same on the heads. You can pull the cams and rockers without touching the valve shims.
3. Inspect cams and rockers for wear, replace as needed.
4. Split case and pull the crank and rods. Inspect and replace parts as needed.
5. Spend $$$ and reassemble.
 

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Thanks for the info, everybody.

Is there a reason that I should re-shim the crank? What advantage comes from doing that vs. not? Some quick googling and ebaying has found 748 motors for about $1,000 plus. If i'm going to do the work myself, it sounds like I might be able to get away with ~$500 in parts? I know I need new big end bearings, and assuming I should get the crankcase gasket kit as well? What else would you guys replace while you're in there?
It won't cost much to do the work as long as the crank is fine. If it is, then the rods are likely fine too. Crank stays locked/bolted to the right side case the entire time. It does not have to come out.

Cost: (will vary)
Crank nut for the flywheel if you do not have Nichol's double nut setup. $28
Head gasket set from Cometic . $62
Big end bearings. $55-75
Gasket sealant for cases and crank case cover. $8.99
Coolant. $8-12
Oil. Depends on how much of a snob you are.

Total: Not much.


While I was in there, I would:
-Check the condition of the sprag and starter gear
-Install a lighter flywheel
-Maybe remove the back cover of the starter and clean things up in there.

I believe that reshimming the crank if for reliability.
 

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Discussion Starter #20 (Edited)
Update:

Got the motor out today. I pulled the oil filter screen out, and found a decent amount of debris in it. There was mostly what looked like rocker flaking in it, I'm sure you guys could confirm by looking at the picture. I'm not sure but I assume from pictures that rod bearing bits would be silver and not brass.

The oil drain bolt :




Oil Filter Screen :




Engine is out! :




I've done timing belts and valve adjustments on my 996, but am not an expert on bearings. I think I'd go in the following order... based on hearing of the particles you are getting.

1. check timing belts and timing - did a belt jump a tooth?
2. Pull the motor out and drop the pan. Clean all the passageways and residue out. Do the same on the heads. You can pull the cams and rockers without touching the valve shims.
3. Inspect cams and rockers for wear, replace as needed.
4. Split case and pull the crank and rods. Inspect and replace parts as needed.
5. Spend $$$ and reassemble.
Thanks for your input. I will start tearing down the motor tomorrow, and will start by checking the timing. It looks like I may also have a rocker arm or two to replace judging by the oil filter screen debris.


It won't cost much to do the work as long as the crank is fine. If it is, then the rods are likely fine too. Crank stays locked/bolted to the right side case the entire time. It does not have to come out.

Cost: (will vary)
Crank nut for the flywheel if you do not have Nichol's double nut setup. $28
Head gasket set from Cometic . $62
Big end bearings. $55-75
Gasket sealant for cases and crank case cover. $8.99
Coolant. $8-12
Oil. Depends on how much of a snob you are.

Total: Not much.


While I was in there, I would:
-Check the condition of the sprag and starter gear
-Install a lighter flywheel
-Maybe remove the back cover of the starter and clean things up in there.

I believe that reshimming the crank if for reliability.
Thanks.

The crank nut - That will need to be replaced? I take it once it is removed I should not re-use it?

Head gasket set - If I do new gaskets, will I need to set the squish? Or is that only if I replace the base gaskets? Is there a negative to retaining the stock base gaskets if the are not damaged?

Bearings - Should I buy new bearings for both rods? I assume the blown rod will be quite obvious one I have the case cracked open.


Thanks for the note about the sprag and starter gear. I didn't even know what a sprag was until I just googled it. I love to hear the things people would do once your this deep in the motor, better to get it done now while it's apart rather than get it put back together just to have something else go out down the line.



What would have caused this failure in the first place? This was the 3rd track day on this oil, and the oil color was still looking good through the sighting glass. I didn't over rev the motor, but I was upshifting without the clutch and the track has a very long straight, getting to 150mph leaves the engine near 9-11k for a good duration. I'm new to Ducati's so I'm not sure if this is a super common thing or not!
 
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