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____ Before I go-on (in a week or so) to fully explain the object of this thread-post, I thought it might be somewhat entertaining to first let everyone have a chance to test their ability to try solving a puzzle of sorts...
__ In the combo-picture posted below, I present a metal-piece which came-from within a stock OHC.single,, and the primary-question posed (to anyone who has a fair guess), is what this piece could possibly be,, (and if you're particularly DUCATI-smart), and then next, what it's intended function could possibly be.
__ Have fun pondering it fellows !


Mystery-Cheers,
DCT-Bob

Without knowing the size of it from the photos, so just going by the shape and witness marks, It looks like some sort of filler piece for a mismatched upper/lower bevel gear oldham coupling. It exhibits wear consistent with the outer edges of an oldham coupling and also it's associated circlip trench. An indication od size might help somewhat, as it could be a filler part for any mismatched oldhams coupling such as tacho drive, for example.(although the witness marks and metal used would indicate to me somewhat higher loading than a tacho drive.)

That's my best guess, anyway.

Kev

It does look like the broken end of a semi-circular coupling shaft?

Not really an Oldham, as I think those have the ability to allow shafts to be off-centre?
In the case of Ducatis' bevel shafts, they only allow lengthways variation.

I know I've seen this before,,hmm thinking....

Thevin wrote:I know I've seen this before,,hmm thinking....

____ Thevin helped me find this item & took the pix for me.

____ LAST-time I listed such a thread-post as this, I don't think ANYBODY bothered to post a response.
I guess this-mystery won't last the better part of a week, as I had expected. ...
__ Since already both Kev & Jordon have now narrowed-down the place where the piece in question is meant to be fitted, the only question still left is what possible specific-use could the mystery-piece serve ?
__ (If anyONE else in the world has ever thought-of having such a handy piece, I would've expected em to be Eldert).


Mystery-Cheers,
-Bob

gauge part to check if the oldham coupling surface plan is still within tolerances? dropped in the cylinder coupling part then you can use filler gauges between the two oldham flat surfaces..
sorry my english is still not perfect

Looks a bit rough and "makeshift" to me, though the photo's are a bit out of focus to see too much detail. Maybe it's been used in conjunction with a longer sleeve and bevel dot movement, to use 250 bevels in a 350 or something similar. Whaterver I don't think it came from an "original stock" 250 unless it fell in during assembly at the factory. Maybe thrown across the factory floor to wake up a sleeping worker after a good Friday lunch time vino session

Nigel

____ Okay fellow-members, this puzzle-challenge is now over-with,, as Nigel has pretty-much filled-in the last blank. ...

[quote= LaceyDucati ...
" Looks a bit rough and "makeshift" to me, "

____ Indeed, a "makeshift" item ! _ (Explanation coming-up below.)



" Maybe it's been used in conjunction with a longer sleeve ,
to use 250 bevels in a 350 or something similar. "

____ This explanation-guess is quite close-enough, and-so brings to an end this 'members-challenge' !
____ The piece in question was conceived & formed into it's new state of shape by myself for the purpose of saving myself much time-consuming work ! _ As with the use of it, I could then relatively quickly install complete-cyl.heads from nc.250-engines onto either wc.250 or nc.350 engines, or complete wc.250 or nc.350 cyl.heads onto wc.350-engines. ...
__ As anyone-else here who has ever tried to swap-around such cyl.head fitments has learned, it's fairly/overly time-consuming to have to swap & properly shim the upper bevel-gears (of a complete-cyl.head) every time a cyl.head with a too-short tower-shaft is to be tested-out on your intended cyl.head test-motor ! - (I used to race with different cyl.heads at the track, so-as to be [relatively quickly] able to compare power-characteristics of various 250/350-cyl.heads with different camshafts, etc.)
__ A "longer sleeve" (for the secured-meshing of upper & lower tower-shafts) was-not needed, as I'd simply place a lift-spacer -(inner-race of a busted ball-bearing) underneath the stock-sleeve.
__ The only other change needed to be done, so as to get the new/reset valve-timing back in sync with the ign.spark-timing,, is to simply loosen & pull the points-cam/AAU and flip it 180-degrees from it's regular/normal-position.



" Whaterver I don't think it came from an "original stock" 250 "

____ I'm sorry I couldn't come-up with more specific wording that would surely prevent such misinterpretation as could understandably be taken as you've done !
While writing my post, I was aware of such possibility and tried to help avoid it by rather using terms such as "piece" & "item" instead of 'part', etc.
However, the FACT remains that the 'piece' ACTUALLY-did indeed come-from "within a stock-OHC.single", (exactly as I had actually claimed in my original post above) ! ...
Back in the early-'70s,, using a tappet-grinder, I machined-out the piece from the lower tip-end of an upper tower-shaft (which was originally removed from a stock 250M3, which had had it's bevel-teeth utterly destroyed). _ So I really can't justify my statement about it's origin being outwardly-misleading.
Sorry that my TRUE-clue could still be so misleading as it could be, (as you have happened to take-it) !



____ After years of wishing to submit this thread, I've finally gotten-around to doing so with the assistance of fellow-member 'Thevin', (who was helpful with getting the item removed from it's past location [in a wc.motor]) !


Dukaddy-DUKEs,
DCT-Bob

Ingenuity and needs must leads to all sorts of solutions!

Thanks for the puzzle Bob.

I've a few unusual things I've found in engines myself, maybe I'll dig some out for amusement