Anyone heard of problems with Nichols head studs?

[monsta]

Maybe something else, but the problem is that my head studs keep coming loose.
A while back I noticed a bit of a fluttering noise under load, when I checked the head stud tension I found that a couple of them had come loose.
I re-tensioned several times but the problem got worse until when checking them found that the threads were starting to strip from the cases.
Anyhow they were fixed with inserts.
Now its doing it again with other studs.
I'm at the point where I can re-tension ok but they come loose again.

Dont know what is causing this but after talking to someone way clevererer than me, it was suggested that because the Nichols head studs are a lot beefier that stock one's they may not allow the normal stretch required of a bolt/stud under tension.
This could cause loosening because of expansion/contraction of the heat cycles until the weekest point (being the thread in the case's) gives way. All theory ATM
Anyone else heard of this problem?
Got to the point that when I (finally) got the bike on the dyno yesterday we couldn't continue because of this drama! (good numbers on the first runs though! )
Anyhow, I'm thinking I'm going to re-install the stock studs, re-coil the threads for extra strength and see how it goes??

[koko64]

Maybe replace with the APE studs from CCW?
If the stock studs are the shiny stainless looking ones, then throw them away, they will give you much worse issues like breaking flush with the case. The Ducati OEM hi tensile studs are an option which retrofit. Iirc, they are the B numbered retro part that also came on later Monsters and 996s, etc.

[koko64]

PM sent about my experience with the stock early studs .

[monsta]

yeah, replaced the stainless ones years ago after my own drama's...
still got em at home, I'm a bit of a hoarder like that! 

[Speeddog]

I've recently built a hot 900SS motor with the CaCW/APE studs, no issues so far.
But it's not got many miles on it, so YMMV.

They're bigger diameter than the OEM studs, not sure how much.

From internet images, the Nichols studs seem larger yet, though they do have a short necked down part in the middle.

In this application, as the length is the same, and the material is the same (steel, excluding the allegedly stainless old OEM ones),
it's only the diameter that determines how 'stretchy' they are.

[monsta]

yeah, I remember them being wasted down in the middle, but never measured them.
I'll have a better look and chuck a vernier on them when I get into it..  Maybe next week??

[brad black]

are the nichols smaller at the thread od?  strange they pull the thread out of the case.  oem ones are waisted, whereas the ccw ones aren't.  but neither should be an issue.

[monsta]

I wouldn't think so Brad. Thats would be something I would have noticed for sure.
They look fine at the nut end....
But I'll check when I get it apart next week.

[monsta]

they're a fair bit more beefy than the stock ones, and where they're wasted down they measure .2mm thicker at 7.76mm.
so, no where near as much stretch...

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