crank bearings knocking?

[Witzie]

My engine is beginning to develop a knock about 3000 rpm clutch engaged or not engaged. It might be the crank bearings but i will have to investigate further. I might have to replace them.
I have medium wrenching skills but i am a quick learner . Is it doable for me to do it myself? Do i really need the special tools from ducati?

[angelix]

if there is a problem with the bearings, you will notice it at ANY rpm speed, it will be lower at low RPMs and will increase with the engine speed.

the bearings on the old Ducatis (things will chage with the new 4valve Panigale) are "conical" and when assembled from ner will require a PRELOAD (refer to workshop manual)

it is very unlikely they could go wrong, unless there is a problems somewhere else.

IF the knocking comes from the conrod "plain" bearings, the noise will get worse the more you use the bike and ultimately you will end with a conrod broken... long before reaching that point you WILL find lots of traces in the oil (the plain bearings are very very soft and will fill the oli with particles) and in any case the noice will follow the pattern described above.

before thinking for the worse, I would triple check all items that could vibrate and in particular the exhaust, cometimes they get loose and can become a source of noise and vibration.

Anthere VERY important thing, sometimes the FLY WHEEL get loose that might cause the noise you hear...

[higgy]

First thing I would do is get an oil analysis done. For less than 25USD you will know the answer. I can't think of anything else on a Ducati you can do for less even when you do it yourself

[Witzie]

the conrod bearings was on my list to check, the flywheel wasn't. Thanks for the advice.
By the way, the flywheel... Where can i find it?

[paso750]

In the workshop and parts manual
It`s under the left/alternator engine cover. You`ll need a puller to get the cover off.

http://forums.ducatipaso.org/viewtopic.php?f=2&t=5168

G.

[Witzie]

I filtered the oil, this came up:



Aluminium particles (not magnetic) and a piece of plastic.

I have a bad feeling about this

[Skins]

Do you think the plastic could be from an oil container, like the seal at the top of a bottle?

[Witzie]

yesterday I found out that one of the previous owners has used liquid sealant to seal the left cover. It's probably a piece that fell of on the inside, it's matches the color. I am more curious about the origin of the metal particles. Maybe from the aluminium engine block parts?
About the knock, it is very hard to pinpoint where it comes from. What makes it more difficult is the fact that i can hear the noise only when I have my helmet on! When i am driving it 's the most audible, it starts at 3000 rpm, when i open the throttle more it doesn't become louder, it just kinda stays there. Also I cannot feel anything vibrating more than usual.

Any way, I changed the oil from 10w40 to 20w50 fully mineral. The knock seems to be slightly less audible but that could be wishful thinking too.

[jayh]

It's not induction noise Witzie ? the carb makes a funny noise under load on my bike at those rpm,not really a knock more like a subdued exhuast note.
The guaze strainer on the pump inlet will stop all of that plastic crap in your oil getting into places it shouldn't,so it's unlikely to cause too much of a problem.

Angelix is right these engines are virtually bullet proof,as far as mains,big ends go unless they've had crap oil in them,so check all of your ancillary stuff like : clutch hub retaining nut,(wobble clutch basket while you are there in case it's loose),cam pulley nuts,altenator nut,engine mounts etc.It's probably something simple. J.

[Mc tool]

Another ( horrible ......sorry ) possibility is that the bung on the big end of the crank is comming unscrewed ( not unheard of ) this eventually fouls the inner case and scrapes of slivers of ally. the blue stuff could easily be liquid gasket but those bits of metal look to me like they are part of something rather than shreds of damaged metal ...... buggered if I can think what tho

[paso750]

I would think, too those pieces are from the housing. They look brittle so they are most likely from a cast part. Reading that someone already had the left engine cover off I probably would start looking there.

G.

[jayh]

They don't look like anything thats been gouged or crushed,more like thin bits of aluminium left over from the casting process ,broken off by what ?,most likely a rough operator