allmost lost alternator nut!

[Brutus]

Gents, today I allmost lost the alternator nut while driving. After removing the alternator cover it appears to be hanging on to the washer behind it.. I'll try to discribe the 'symptoms': at first the battery lamp stayed on for a long time. I think it took about 15 minutes before it turned off. Furthermore I feld a vibration through the bike and after a while it got worse. After half an hour I got off the highway and had to stop at a traffic light. It didn't run smooth when idling. Allmost like it run on one cylinder. On the other hand it didn't stall when running stationary. In the end these symptoms can be explained cause the rotor wasn't fastened and had some freeplay.. Hope this helps fellow paso-brothers in the future to avoid damage..

[Mc tool]

That was lucky ! I hope there is no major damage . The only thing I have ever heard about the alt nut is what a bastard of thing it can be to loosen , but there you go

[JWilliam]

Amazing there is no engine damage! Normally the hex undoes and the flywheel rotates on the shaft crushing the woodruff key & breaking the crank. Seen this done to an 851 - what a mess.

[paso750]

correct torque and Loctice are crucial. Ducati recommends to check the nut on regular Basis but who does that ?
The lock washer should be checked as well and never be reused.
There`s also this solution but I find it rather pricey for two nuts:
http://motowheels.com/i-10781667-corse- ... ucati.html

G.

[Brutus]

I think its all about torque. The manual states approx 118Nm (chapter Engine Re-assembly) and the torque table in the end of the manual states 137-147Nm. On the other hand the manual of my 851 suggests approx 180Nm. I believe the latest ducs need more then 250Nm for the alternator nut. I got it all together again with 180Nm of torque. Also fitted a new sprag. Currently the liquid gasket needs some time to set properly and then it's back on the road

[Derek]

On my previous ST4s the flywheel nut torque was 230Nm with a special one time only nut. For my current MTS1200 the flywheel nut gets tightened to an unbelievable 330Nm!! ... and Loctited!

[paso750]

and there`s a belleville washer or a lock washer (to bend over the nut), too.
Newer rotors must be different as I`ve heard of a couple of old ones that split when torqued over spec.

G.

[higgy]

you need to check your clearances before this happens and make sure the washers are in place as they tend to fall down with even small taps