Cooling slots on Mk3 Front Brakes

[DewCatTea-Bob]

[quote= Moto Chuck ... "
" On my 250 Mk 3 both the inlet and outlet slots are open. "

____ It seems my rather hasty/(unedited) post-wording hadn't properly taken into account that the available ex.slots on the brake-side may've also been opened-out, (as I was then only thought-picturing just the right-side cover in-mind).
Sorry for that oversight being left overlooked in my previous post.



" The slots are exactly as wide as the fake slots on the rest of my half dozen or more backing plates and hub covers
if it wasn't factory somebody did a bang-up job on cutting these slots because they look absolutely factory. "

____ It does stand to reason that a personality who'd bother to go to the finer detail of opening the 'slots' just as they are meant to appear, (instead of rather simply drilling holes for just the actual functional purpose), would also care to bother with doing a GOOD/meticulous job at it. _ And also probably care to further carry-out the intended subterfuge-ruse of also completing the (actually functionless) appearance-deception on the right-side hub-cover as well.



" I can post pictures of the backing plate "

____ That would be nice to see for us all, (with hopes of an adequately lite close-up pic.view showing the finer detailing of the cut slots) !



" I would have to check, but I have a friend with another NC 250 Mk3 that as I remember, also has the open slots in both front hub covers. "

____ It could've been helpful if such a feature was common amongst all Mark-three models, as it then would've been another useful factor for helping to identify Duke-models from one-another.
However I'm quite sure that if most others of us check,, they'll not fine the slots to be open, regardless of model-type !
____ Have you ever checked to see if any air-flow ventilation hole-openings were also made in/through the (otherwise closed-off) hub-wall behind the right-side hub-cover, (so as to make the right-side inlet-slots actually functional as brake cooling) ?



" Alternatively this could be another of those "What's in the parts bin today Luigi?" parts flukes. "

____ It's my-own fairly-good opinion that that somewhat wide-spread notion is way overblown,, cuz for within the USA.market, I've always found pretty-much near 100% parts consistency for most all original-stock model-lines ! _ In fact, I can't recall EVER seeing any part (on any stock model) that wasn't exactly as indicated within factory parts-books !



" I believe that Grimeca was responsible for the brakes and they may have had some slotted hubs and RH cover plates that they sent Ducati at some point. "

____ It doesn't make sense to me that they would bother to also have open-slots on the RIGHT-side cover-plate as well,, as it would be a wasted effort, since it would be FUNCTIONLESS (without also adding ventilation-holes through the hub-wall) !


____ It would be nice to have some other Mark-three owners chime-in (after checking their-own air-scoop slots), to confirm that open-slots are-not a stock feature.
__ I frustratingly haven't been able to find my old/n-c.parts-book (since last-fall when someone entered my home & moved-around my belongings, while I was hospitalized), so I-myself can't double-check to see if the Mark-three front-hub parts are possibly indicated to have different part-numbers. _ So perhaps someone-else with such a parts-book, can check on that for us. _ Cuz if there really was any such common difference, then the varied part-numbers would reflect it.
But however,, I'm rather sure that all the varied models' hub-parts are the same, as far as the scoop-slots are concerned anyway.


Dukaddy-DUKEs,
-Bob

[Moto Chuck]

Bob,
For extremely well documented non-standard parts check the tail light assemblies on narrow case singles. All of the parts books I have ever seen had the square tail light but most of the NC bikes I have seen had the round CEV tail light with accompanying license plate bracket. Both Mick Walker and Tom Bailey have commented on this. Standard electrics on these bikes were also at times a moving target with manufacturers changing due to purchasing or availability decisions.

I would agree about the relative uselessness of RH cover cooling slots without vent holes in the hubs but it would provide minimal cooling to the hub and bearing carriers. Not a great help IMO but some help all the same.

It would indeed be helpful if there were more of these differences in the spec parts of Mach 1 and Mark 3 singles as it would keep folks from restoring lesser bikes into Mach 1s and Mark 3s and passing them off for sale.

[DewCatTea-Bob]

[quote= Moto Chuck ...
" For extremely well documented non-standard parts check the tail light assemblies on narrow case singles. All of the parts books I have ever seen had the square tail light but most of the NC bikes I have seen had the round CEV tail light with accompanying license plate bracket. Both Mick Walker and Tom Bailey have commented on this. "

____ I've been unaware of what those two fellows have commented about your supposed example of a part that wasn't kept consistently standard-issue equipment on a Ducati model-line,, but apparently it's really not "well documented", since that particular suspect-item doesn't really count as such an irregular production piece ! ...
The reason why that supposed example seems to promote the haphazardly-employed parts myth, is actually logically due-to a rather reasonable circumstance ! ...
While Ducati preferably chose to employ the rectangle-taillight & square plate-bracket setup for all other world-markets,, Berliner rather required the round-style taillight & associated plate-bracket setup, for the 'USA' market, (presumably for the same reasoning as why the USA.market required the 'sealed-beam' type headlight [instead of light-bulb] and it's-own alternate rim-bracket version).
__ So the 'Made for USA' models are sort-of like different-models of otherwise identical model-lines, and-so ought-not be assumed as inconsistent-versions of the very-same model all taken from the very-same model-line ! _ As the 'USA.models' were of a separate model/production-line which was kept pretty-much standardized with it's own particular parts !
And many parts-books obviously indicate their 'Made for USA' model pages.
__ So you ought now understand why your proclaimed example is unfair to submit as a valid exemplar-paradigm -(case-in-point).
____ I challenge anyone to come-up with an ACTUAL example of any stock part that wasn't fully intended to be left consistently remaining as a common production-line part (which was only relatively briefly employed as a non-permanent stand-in, for any model-year).



" Standard electrics on these bikes were also at times a moving target with manufacturers changing due to purchasing or availability decisions. "

____ Can you actually provide word of any real example of such, (which wasn't merely a regular-type upgrade due-to a rather ordinary model-year change-over) ?



" but it would provide minimal cooling to the hub and bearing carriers. Not a great help IMO but some help all the same. "

____ Of-course I couldn't disagree with that, but apparently it wasn't considered by the factory to actually be enough help to be worth having.
__ I've now developed some positive thoughts about this, which I'll make mention of within my next-post.


Duke-Cheers,
-Bob

[machten]

Here's a pic from my '68 twin filler front brake. It is not the same as other "less convincing" fake vents I have on others. This looks like real vents. They are not. Whilst they are positively cut, they do not penetrate. Dunno if it is relevant, but thought worth sharing...

IMG_1460.JPG

Kev

[machten]

The other side...

IMG_1461.JPG

Kev

[DewCatTea-Bob]

[quote= machten ...
" Here's a pic from my '68 twin filler front brake. "

____ Actually meaning your w-c.250Mark-3/DESMO model, I believe.



" Whilst they are positively cut, they do not penetrate. "

____ But they really do appear to go-through in most expected areas ! _ So how is that seemingly so ? _ Has black-paint been left applied in just those areas ?
(Do you care to admit of ever being really-fooled by that added rose-work ?)
__ Do you have any notion to complete the penetration (for the full-length of all the slots) and make them rather 'functional' ?



" thought worth sharing... "

____ Definitely "worth sharing", as it's certainly quite relevant enough ! _ Although it would've been dead-on relevant if your Mk3 had been a n-c.version (showing that the slots are still not functional).


Enlightening-Cheers,
-Bob

[Moto Chuck]

Well I dug into the front wheel this eve. Here are the pictures. You can see the light coming through the slots in the RH hub cover.




The brake shoes were blocking the light to the slots on the brake backing plate so I just took a pic of the plate from the front. You can stick a piece of thin cardboard through the slots and it will come out behind the brake shoes.


The slots do look to have been machined. I can't say whether this was done by Grimeca, the dealer or some time after the bike was purchased. The other Mk3 I have seen with real slots came from the same dealer here in Kansas. The bike is titled as a 1967 Mk3 and I bought it in 1984 and have owned it since. These are the only two 250 Mk3 narrow case bikes that I have paid attention to the front brake setup. My front hub does not have any holes in the web for cross ventilation so the slots on the RH hub cover are of minimal functionality at best.

I have a bunch of other RH hub covers and brake backing plates with fake slots.

[DewCatTea-Bob]

[quote= Moto Chuck ...
" Here are the pictures. "

____ Thanks for your thoughtful pix.
__ Didn't expect you to dismantle your wheel in order to take them but, that extra trouble not-only allowed you to take your internally lite-up pic.shot but also allowed you to check & see if the opening-work of the right-side slots came along-with any included additional venting-work done through the hub-wall (so as to make that questionable right-side slot-venting actually functional).
And also, it would be of related interest to see right-side & left-side pictures of the wheel-hub, (while you still have it apart).



" The slots do look to have been machined. I can't say whether this was done by Grimeca, the dealer or some time after the bike was purchased. "

____ Well I wouldn't even suspect that slot-venting work to have been done by either factory, especially now that you haven't found any collaborating air-flow venting* completed through the hub-wall (* which ought best be located somewhere between the speedo-drive & the hub-wall's outer-edge).



" The other Mk3 I have seen with real slots came from the same dealer "

____ It would be of interest to closely compare the slot-venting work of both examples, to see if it's all exactly identical cutting-work.
The slot-cutting work on yours does appear to have been done by someone who actually cared to do superior looking, (although not 100% functional), vent-work.



" My front hub does not have any holes in the web for cross ventilation so the slots on the RH hub cover are of minimal functionality at best. "

____ RIGHT, and that's good/collaborating evidence that all that (non-stock) slot-cutting was most-likely done by a previous-owner !
____

__ I've now developed some positive thoughts about this -(air-scoop vent-cutting mod), which I'll make mention of within my next-post.

__ So as to address the possible wet brakes issue (due-to opened-out vent-slots), as Jordan has previously pointed-out, and yet also retain functional air-scoop brake-ventilation,, I'd suggest keeping the LEFT-side inlet-slots blocked-closed, and make some (thoughtfully placed) vent-holes through the hub-wall.
That way, any rain & puddle water entering the slot-modified right-side air-scoop, will be rather spun/flung-out* of the ventilating-air flowing through the hub-wall & into the brake-hub side, and then the waterless-air will become vented-out the left-side air-outlet slots (of the brake/hub-cover's rear-facing scoop).
(* Somewhat rather centrifugally, outward around the outside-edge of the right-side hub-cover.)
__ Anyone who cares to go-through with such rather thoughtfully functionalized air-venting, will get further related details from me, to help keep water from getting trapped within the brake-workings.


Enlightened-Cheers,
-Bob