848Evo Main Bearing gone

Dry slipper is a pain in the arse to get off!

 

Out of interest what were the symptoms just so i know what to expect should it happen to mine.

Is it noise or vibration etc ?

 

The main bearing going is common across the range of Ducati's from 748/9** to 999 to 848. My 748R lost a main bearing at just 4,000 miles. I would get the big ends checked on the crank at the same time or even replaced.

There is a thread running at the moment where someone with a 999 has lost their main bearing doing a trackday.

Blueprinting is worth it as your engine will be set to the optimum spec as far as tolerances go and Ducati's engines built at the factory are often pretty slackly set up, blueprinting can release a small amount of power but mostly it is about engine longevity.

 

This statement really worries me, and I think it needs some clarification? surely if it was a massive issue Ducati would be dealing with it as a recall, or an open good will like we have seen from other manufacturers?

I am not saying your wrong or that it isn't happening, but how many bikes is this really happening on compared to those sold?

 

I have experienced this on 2 748's both of similar years, others have experienced this too so it's more than an isolated case\s. What I am saying is it is not a totally one off incident, it is simply not uncommon for this to happen. You can draw your own conclusions, as Ducati may not see this as an issue compared to the number of bikes produced. The fact is that it is certainly more common of this being an issue with a Ducati compared to other manufacturers.

How many people actually do anything about reporting this to Ducati? I didn't, as my bike was several years old and well and truly outside the warranty period as was the other that I had that went. The fact is this happens on quite low mileage machines and I know of other personal examples including a low mileage 998.

 

I've gotto admit, when my 996SPS blew it's gearbox, i was shocked to see how badly made the engine was. I changed all major bearings and opened up the oil ways. Not for fun, but because i had too.
I'd say while it's apart you might as well do some tweeking. I had mine blue printed and it's so much stronger and smoother it must've been knackered before the box went. Less than 10K on the clock with that too.

 

I am shocked at that on a new design engine.
that should not happen

 

Fundamental flaw maybe? It's not a totally new design but more of an evolution. These engines now produce more power than they did or possibly were even made for originally. There is little doubt that if anything will go first it will be a main bearing and it is highly likely to be on the flywheel side.

 

Initial symptoms ?

I'd like to catch mine before it gets nasty should they ever start to go bad (touches wood)

 

Yes, what were the symptoms? at certain revs the bike vibrates like mad anyway, so how do you know?

 

On the 748 - 9**series the alternator case cracks and you get hairline fractures around the case outrigger bearing after that you will find metal in the oil as you might expect.

I lost two crankcase covers before it got bad enough to diagnose, admittedly one case was damaged and badly repaired before and that was down to a crash, not by me I might add, so the true extent of the damage in the accident I will never know but it punched a small hole in the casing which is not unusual for a nearside crash on the 748 -9** series. I repaired it and it lasted 100 plus miles but when when the bike was being setup on a dyno it went again so it must have had a number of runs up to maximum revs but still wasn't detected.

If it goes it's usually to late to know unless you start feeling vibration and can pin it down to the nearside of the engine and even then the bearing will have gone at least.

I was lucky no case damage only alternator side casing and bearings gone. I might add that my big end bearings were also found to be going on strip down. Check my previous posts about 999 bearing failure to see the extent of the big end wear.

 

Okay, thanks for that. It's new to me so my only comparison is the demo bike so I'll keep an eye out for it.

Are all these cases all when the bike has been run in-by the book? or literally random? not saying that there is anything wrong with revving more than 6k as long as the engine is warm etc; just wondering if it is literally just down to Quality Control on the bearings

 

Preload on the main bearing\s when the engine is built from new seems to have an effect. When my 748R went it was suggested that the preload from the factory had not been good enough and whlist within limits it was on the tight side and had caused premature wear. To give an indication one engine went at 4,000 miles and the other at 22,000 (not bad!) miles so there is a big difference, yet the age of the engines in question were similar. It is something of a pot luck situation and it seems that this is unpredictable. It depends on who built the engine at the factory.

Care and maintenance don't seem to come into it, apparently it is how it was built from new. This is what, to me, makes blueprinting much more of a sensible thing to do as it's mostly about longevity.

There is only so much you can do to stave this off and if it is going to throw a bearing it will! and maybe the answer is a different way of setting up main bearings on these engines and better attention by the factory. As I have mentioned in my posts above this is more than could be expected in terms of numbers, it's not a one off incident, in my opinion and some others who have worked on these engines that this is too regular an occurrence.

What tends to mask these "problems" is that many people don't do big miles on their bikes. As an example my 998 which I purchased from new has done 4,000 miles if a main bearing goes, and they do, what am i going to do? There would be no point going back to Ducati as I know they won't entertain any sort of claim.

 

My keen interest is mainly because on a recent tour of Spain i became aware of a distinct increase in vibes through the seat especially mid range. Wasn't really aware of more noise in general. It could be innocent and a loose exhaust bolt or something as not ridden it since or been over it but Main's were in the back of my mind.

Short of pulling it apart it's tough to make a call so might just have to see if it gets even worse. Unless something shows in the oil etc.

 

You can take the side casing off and check for movement of the crank main bearing by rocking the flywheel, any movement is likely to indicate the main bearing is going. The side case is only held on by sealer but it does mean draining the oil but it will cost relatively nothing to check it.

 

Or lean it over carefully and you'll not need to drain the oil down ;-)

 

When you say "rock the flywheel" you mean...?