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Recently the gearchange return spring on my '03 ST4s broke. I will be replacing it this week but, unfortunately on all Ducatis since 1999 with the 3-phase alternator the flywheel has to come off to get the gear selector out. When re-fitting, the manual says to use a new nut, lubricate the threads and torque to 220Nm. Fair enough, but given the flywheel nuts reputation for coming loose I reckon blue Loctite on assembly would be a good idea. Any thoughts?
 

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Old Wizard
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Ducati Flywheel Retaining Nut Problem

On an '03 bike you just need to retighten the nut to the correct torque. 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.

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.

History: For the 1999 models, Ducati redesigned the electrical system, going from a 350 watt design to a 500 watt three-phase system. This resulted in a new flywheel retaining nut design that, unfortnunately when produced, had an oversized thread depth that would loosen-up, even when properly torqued and Loctited.

The factory installed these 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 manufactured out of tolerance. (If you have one of these bikes, you should have it checked.)

Ducati issued a service bulletin concerning the stock nut. If the nut spins-on with little resistance it’s out of spec and must be replaced with an upgraded nut from Ducati. An different rotor was introduced for the 2001 model year that put an end to the issue.

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

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Beta Tester
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the literature i have says RED locktight.
 

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Member
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the literature i have says RED locktight.
I think I read something written by LT Snyder, perhaps is his ST maintenance book, that the new nut style comes from the factory with red locktite, and one shoud apply heat to it before trying to remove it.
 
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