[Ducati] Which 900 engines had the bad studs

[Nankervis, Wayne]

Depending on the application, different grade fasteners have different
torque values.  Along with that, torque values are assigned for both dry and
lubricated applications.  Typically, again depending on the application,
lubricated higher grade fasteners can achieve much greater torque values
than lower grade fasteners in a dry condition.  Consult your shop manual for
recommendations.

Wayne  

-----Original Message-----
From: ducati-bounces at ducati.net [mailto:ducati-bounces at ducati.net] On Behalf
Of Ronald Betts
Sent: Tuesday, May 02, 2006 10:05 AM
To: ducati at ducati.net
Subject: RE: [Ducati] Which 900 engines had the bad studs

I guess I have to add my 2 cents worth. As a automotive tech for over 25
years (now retired) I replaced lot and lots of head bolts which would eguate
to Studs on a motorcycle. The reason for the replacement was due to the fact
that the bolts were a expendable part,. The reason was , the bolts were
designed to stretch with the heating and expansion of the head in relation
to the block. In the case of Studs it controls the stretch due to the
expansion of the head and cylinder. Repeated stretch cycles would require
the replacement of those bolts. Some of them are even rifled to help with
the stretch. As far as the question of lube on the threads is concerned I
found that using any lube gave me a false torgue reading leading to bolt
failure as it would always cause over tourqeing. I am from the school
(meaning comebacks and poor longivity of repair made) that taught you to
take the time to make damn sure that the threads in the block were clean dry
and in good shape. That meant alot of running a tap in the bolt holes as
part of assembly prep. Once I started doing this the comebacks became non
existant. This is the procedure used by every top machinest I have ever
talked to including Pops Yoshimura and the wrenches in the NHRA pits. I may
be wrong but the evidence is clear to me, Don't Lube the Threads as it will
lead to a false torque reading.
And now, let the arguing comence!


Peace...Ron"Desmohead"Betts 95 900 SP
I've learned that I don't suffer from insanity, I enjoy it!





>From: Rich Roberts <bigredxrunner at yahoo.com>
>Reply-To: Ducati Owners Group <ducati at ducati.net>
>To: Ducati Owners Group <ducati at ducati.net>
>Subject: RE: [Ducati] Which 900 engines had the bad studs
>Date: Mon, 1 May 2006 16:08:15 -0700 (PDT)
>
>Uh okay...what does that mean, fastener is designed to stretch to give 
>you the torque? Interesting, since threads are a big part of that 
>torque as well as the amount at head, the thing that always scares me 
>about such things is exactly how do you standardize the procedure of 
>torquing, how much lube on threads, what kind of lube etc etc. As we 
>all know lubrication changes things in a big way. Use too much or the 
>wrong kind and torquing becomes an exercise in futility until that 
>waisted section breaks. Do you work in the aviation mechanics field? 
>Where do you see such fasteners routinely?
>
>frugalyankee-cycles at yahoo.com wrote:  Some of the 'waisted' fasteners 
>I've worked with over the years are the 'stretch' type (torque to
yield).....
>
>Brad
>CT.
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Ducati On Line thanks its sponsor and friend, Cycle Cat, maker of some of
the most beautiful products ever for Ducati's.
Visit http://www.cyclecat.com/

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