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Discussion Starter · #1 ·
Hi,

I have replaced the ball bearing that presses in the left side cover and connects to the crankshaft on the outside of the stator a couple times. It always wears out and the balls fall out. It must be out of alignment or something? or do I understand there is a fix for an overheating problem? when it fails it makes a lot of noise.

I don't follow why this bearing is even needed, it is on the outside of a very stiff crank that seems to hold the generator electrical rotor in the stator just fine.

Can I simply leave this bearing out or ???

thanks, Matt
 

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Another thought is to be sure you're installing the new bearing correctly. The OEM replacement bearing has an oil seal / shield on one side. Seems odd, but that seal needs to go toward the engine for proper lubrication. Open side facing out. If you've been installing the the seal to the outside, open side in, flip it around on the next replacement.
 

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Discussion Starter · #5 ·
Good info. The one I found in the bike had no seal so I have always replaced with no seals. I'll get a bearing with a single sided seal this time. Ive been installing by pressing on the shaft and then pulling the cover on to it. Is it better to press straight into the cover and then pull it onto the shaft? Also I was wondering about using a sealed bearing so I don't have to rely on engine oil at all?

I still cant figure out why that little tiny bearing is needed on the end of that big crankshaft. has anyone ever just left it out?

thanks, Matt
 

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fit the bearing into the cover, then fit the cover.

leave it out and see what happens, then let us know. i don't expect it will be good.
 

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The one I found in the bike had no seal so I have always replaced with no seals.
I bought the OEM seal when I replaced the one in my 916. Wasn't having issues with it, but i was in there for a light weight flywheel and new stator anyway.

The OEM bearing had a transparent oil seal, probably better called a splash shield. Wasn't what you expect to see when thinking of a bearing seal.

70250081A - BALL BEARING 6003 TN9 C3. $14.96 listed on a Ducati parts finder site.

Did a quick Google search for that bearing designation and none I saw came up with any seal. I think I'd go OEM here to be sure you're getting the right part. You're not saving much if you don't.

Maybe the seal isn't your problem, but it's worth being sure the right part is installed correctly. At least if it fails again, you'll be able to eliminate one item.

The bearing is listed as a C3 radial clearance. Allows for thermal expansion. That's fairly important consideration too. Not sure what bearing you were using, but that should also be adhered to.

Edit. Dug through my pics and found a decent shot of my cover with the bearing (because who doesn't take freaking pics of everything they do???), You can just see the seal I am talking about.
 
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it's not a seal, that's just the plastic cage - that's what the tn9 (or part of) denotes. the other side is the open side of the cage.
 

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Thanks. Plastic cage was mentioned in the bearings I searched. Didn't consider it would be visible from the one side as it is. Makes more sense. I did read when I was doing my own work that it needed to face towards the engine for proper lubrication, however. Looks as if the oil for that bearing comes from the crank end. That is how the original bearing was too. True? No?
 
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