Ducati.ms - The Ultimate Ducati Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I have a 2005 ST3 that I purchased in 2006 with approx. 3000 miles on it. It now has just over 6000 miles. I recently took it to the dealer to get their opinion on some unusual noise. I had checked valve clearences and changed the belts. The dealer felt that the belts may have not been put back on correctly. I agreed to pay them 1.5 hrs labor to make sure everything was put back correct and double check the belt tension. After removing and reinstalling the belts and retensioning them, the noise was still there.

The noise was difficult to discern where it was coming from. It was a ticking sound. I did not notice the noise prior to performing my own maintainence but can't say for sure that it was not there. Also the bike ran a little rough for me upon first ride after I replaced the belts. Upon further investigation, the dealer felt that the noise was possibly inside the left side cover (think flywheel nut!). Once they removed the cover, they found that the flywheel nut had in fact come off the crank and was just sitting there. The threads on the nut were messed up enought that it would not thread back on the crankshaft. Parts were ordered and finally came in Friday.

Today the dealer called me and advised a couple of gears behind the flywheel were worn and they felt they required replacement. I intend to go look at the issue myself before proceeding further. The dealer did not quote prices for parts yet but if it requires the timing gear set it runs about $475 for those.

The dealer mentioned a TSB to check the flywheel nut and I also found reference to it here in post #18:

http://www.ducati.ms/forums/showthread.php?t=40286&highlight=alternator+nut&page=2

The tech stated he saw no evidence of thread locker on the threads of the flywheel nut or crank. I feel this is a fault that Ducati knows about. Either it was not assembled correctly or there is a defect. Neither I nor the dealer are aware of the left side cover ever being off. The tech was also concerned about damage on the clutch side from the nut being off.

What other damage should I worry about here? Is the damage to the gears from the nut being loose or off?

The bike is out of warranty but I feel Ducati should take care of this issue. At this point I am looking at $700 or more to put it right not including the labor for the belts. It does not seem very common on later bikes but Ducati is aware of possible issues since they issued a TSB. The service manual clearly indicates to use thread locker on the nut. I plan on insisting that the dealer contact Ducati NA to see if they will cover some or all of the repair.

Am I on the right path here? Does anyone have any other advice?

Thanks in advance.
 

·
Registered
Joined
·
2,794 Posts
You've done good research. Sounds like the issue regarding funding any further repairs should be between your dealer and ducati. Good luck!
 

·
Registered
Joined
·
1,910 Posts
I'd ask to see the oil pre-filter screen when you get there. If there are metal shavings, that's where they'd collect.
IIRC, the only mating gears to the flywheel are the starter drive gears.
 

·
Old Wizard
Joined
·
3,006 Posts
Ducati Flywheel Retaining Nut Problem

My guess is that the flywheel retaining nut had been removed at some point before you owned it. Here's the background info you need to understand the issue.

In the early ‘90’s Ducati used two jam nuts to secure the flywheel, but replaced this design with a single very-fine-thread flange nut that carried with it an extremely high torque requirement.

There’s two parts to this issue.

First, the factory installed defective nuts on some 1999 and 2000 model year bikes before the loosening problem was caught. These nuts came loose even when installed with the correct torque because the treads were oversized. (If you have one of these bikes, you should have it checked. If the nut spins on/off easily it should be replaced, not just re-torqued.)

Second, the flywheel retaining nut design needs to be tightened to a VERY high torque level to keep it from loosening. It’s the highest-torqued fastener on the bike.

Except for these two model years, you’ll not get a loosening problem unless you’ve removed the nut for some reason. When you go to reinstall it you’ll find that without the proper tools it’s VERY difficult to immobilize the crank (which is necessary to reach the high torque) and many shops/owners don’t understand how critical this is. The use of this kind of nut in this particular application is on the envelope of fastener design.

So I’m not offering any advice here as to how to do it.

Consequently, some owners have decided to replace the single Ducati nut with the two jam nut design offered by Nichols.

http://www.nicholsmfg.com/

A couple adventurous owners have tried Nord-Lock washers with the stock nut.

http://www.nord-lock.com/default.asp?id=3&language=4 **

The point I’m trying to make is that if you don’t have a 1999 or 2000 MY bike. and you haven’t touched the flywheel nut, don’t worry about it coming loose.

Under the circumstances I can't see your argument over this with Ducati.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #5
Thanks to all for the input.

Under the circumstances I can't see your argument over this with Ducati.
I do believe there is still an issue beyond 1999 and 2000 bikes as it is still a known problem as admitted by my dealer. and Ducati has issued a TSB to check the nut on at least some years of the ST3. I cannot say for absolute sure but I do not believe that the nut has ever been removed. The side cover did not look like it had ever been removed and resealed.

That said, Ducati NA certainly could choose to not cover the repair.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #6
I'd ask to see the oil pre-filter screen when you get there. If there are metal shavings, that's where they'd collect.
IIRC, the only mating gears to the flywheel are the starter drive gears.
They seemed to imply it was the timing gears on the crankshaft and layshaft but the service writer did not know for sure. I will find out when I get there.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #7
Just talked to the dealer again. It is the timing gears on the crankshaft and layshaft. Price from them is $468.:eek::mad: I found a used set at gothamcycles.com for $39.99.:think:
 

·
Registered
Joined
·
9 Posts
Discussion Starter #8
Looked at the damage today. It was their opinion that the damage was caused some time ago by a broken gear lever return spring causing the gear lever to rest against the gear on the crankshaft. The spring had been replaced but the worn gears were left. I ordered the used gear set from Gotham and should be on my way soon.
 
1 - 8 of 8 Posts
Top