Cooling slots on Mk3 Front Brakes

[Moto Chuck]

One thing that has always piqued my curiosity is that my 250 Mk3 has real cooling slots on the brake shoe backing plate for the front wheel and the R.H. hub cover. I have never seen real slots on any of the Sebring, Monza, Scrambler, GT or other narrow case 250. (I haven't found out whether the Mach 1 has the slots) I have a lot of backing plates and hub covers that only have cosmetic slots that don't pass any air.

Were these slots just cut on the Mark 3 and possibly Mach 1? Has anyone tried to cut the fake slots on a cafe build, and what were the results? Can you cut the slots and make them look factory?

[Jordan]

I have real air holes on my double sided 350 brake, which work great in dry weather.
They hardly work at all when wet.

[Moto Chuck]

I have real air holes on my double sided 350 brake, which work great in dry weather.
They hardly work at all when wet.

Are you saying that your brakes don't work when the slots let in the rain? Double sided sounds like an aftermarket 4ls setup.

[JimF]

I tried a quick and could not find it, but a fellow on this list opened up his vents and put a screen in front of them that looked incredible and professionally done.

The visual impact was almost like looking at an old 4LS drum brake.

I will continue to search for it tomorrow.

[JimF]

http://www.mts.net/~jkrocker/Duke1/

OK, here it is. Near the bottom of the page...

[Jordan]

Are you saying that your brakes don't work when the slots let in the rain? Double sided sounds like an aftermarket 4ls setup.

Yes, they don't, because they get too wet.
Double sided brakes were standard on the silver-flake and some later desmos, although they were an upgrade on mine.

[Moto Chuck]

http://www.mts.net/~jkrocker/Duke1/

OK, here it is. Near the bottom of the page...

Looks very good. I have a number of brake backing plates and RH hub covers so I may try ventilating a set.

Jordan,
I am guessing that I won't be riding all that much in the rain on the little Duc so it probably won't be a big problem. I remember from back in the day dealing with rain and Magneti Marelli elecs on my old Guzzi Ambassador. Don't think that vintage Italian bikes were meant to run in the rain.

[Jordan]

Jordan,
I am guessing that I won't be riding all that much in the rain on the little Duc so it probably won't be a big problem.

That's an excellent policy. Once I was caught in an unexpected shower, for a scary ride home.

Oddly, some bikes with open scoops don't seem to be affected much by rain.
Some bikes had a scoop that could be closed.
http://www.oldgoldmotorcycles.com.au/bi ... a_1971.htm

[DewCatTea-Bob]

[quote= Moto Chuck ...
" my 250 Mk3 has real cooling slots on the brake shoe backing plate for the front wheel and the R.H. hub cover. "

____ It's certainly most-likely that you can blame a past-owner for that questionable work ! _ Cuz not-only did the factory not make those slots functionally-real for ANY of their models, but they certainly wouldn't have also bothered to open the slots on the non-brake/right-side of the wheel-hub as well, (as that wouldn't pay-off any functional purpose) !



" I have never seen real slots on any of the Sebring, Monza, Scrambler, GT or other narrow case 250.
I have a lot of backing plates and hub covers that only have cosmetic slots that don't pass any air. "

____ That FAKE air-scope feature can no-doubt be attributed to Berliner as just another one of their inspired hair-brained sales-gimmicks !
(To find other thread-posts concerning this, try searching "fake air-scoops" .)



" Were these slots just cut on the Mark 3 and possibly Mach 1? "

____ I've never seen actually functional/opened air-slots in the stock front-brake of that Duke-model or any other !
The (FAKE !)- scoops were merely-just for appearance-sake and never intended to be actually functional, and-so the slots were never cut-open by the factory-itself !



" Has anyone tried to cut the fake slots "

____ I wouldn't advise doing-so. _ It would more-so allow increased dust & dirt into the brake-workings, merely in exchange for some unnecessary fresh-air (under most encountered braking conditions).
And besides, how could cooling-air flow-through, without some kind of air-outlet (to go-along with the inlet-slots), so as to let air (& $#!+) pass-through ?



" Can you cut the slots and make them look factory? "

____ Since the-factory hadn't ever done so, then of-course there's no factory-look to attempt to copy. _ But it seems that you've been fooled by a PO who seems to have done factory-like work, (so perhaps THAT work is worth copying ?).



" what were the results? "

____ Of-course there's already been other discussions of such, in the past ! ... Here are links to a couple of related threads concerning this same topic... viewtopic.php?f=3&t=818&p=5638&#p5638
viewtopic.php?f=3&t=105&p=890&hilit=fake#p890


Dukaddy-DUKEs,
-Bob

[Moto Chuck]

Bob,
On my 250 Mk 3 both the inlet and outlet slots are open. The slots are exactly as wide as the fake slots on the rest of my half dozen or more backing plates and hub covers on the parts pile or spare bikes. I am out of town for the weekend of the fourth but I can post pictures of the backing plate when I get back. As you say, if it wasn't factory somebody did a bang-up job on cutting these slots because they look absolutely factory.

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. Of course both bikes came from the same dealer here in Kansas and it might be that someone at the dealership had some millwork done on several bikes. Alternatively this could be another of those "What's in the parts bin today Luigi?" parts flukes. 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.