Daytona/Diana differences from Monza etc.

[Haggis]

Could anyone tell me the main differences (engine and chassis) between the Daytona/Diana and other N/C Ducatis please.

I am rebuilding Daytona which has obviously had lots of work in the past. I am presuming that it is a Daytona, but can only find workshop manuals which refer to the Monza, etc... The bike has been re bored at least once (74.8 mm piston) The piston is a flat top four ring rather than high crown high compression job. Is this right for the bike? The little I can find suggests that the Daytona was a sporting model, so I was wondering if it had a high comp. piston as standard. Any other clues like number of gears, valve diam etc.. would be most welcome.

The bike came with clip ons including lever brackets welded on. I am presuming that they were OE on the bike, but may have been retro fitted. The top yoke does not have fittings for standard bar.

If anyone has a picture of the seat frame I would be grateful, the bike does not have a seat, but I may have a go at building one.

Thanks

Chris.

[DewCatTea-Bob]

" Could anyone tell me the main differences (engine and chassis) between the Daytona/Diana and other N/C Ducatis please. "

____ Seems as if you'd like an entire book on the subject to be posted, (as your request leaves a whole lot to be covered).
__ I've never owned or even worked on any Duke-model with the name "Daytona", although I think I once seen one in a cycle-mag. _ To help confirm whether your Duke was really an actual 'Daytona', it would be useful to know what year it was actually produced, and also it's motor-number, number of gear-speeds, carb.model, etc.
__ As for the mere name "Diana", that's a name-term that's been well overused & abused by many-others (even ever-since the early-years), and has pretty-much been used by such-sorts in-place of the other/older-term 'Duke'...
It seems (to me) that those who are really 'into' DUCATI-Singles, say: "Duke", while those who are merely into 'bikes' in general, instead say: "Diana",, whenever referencing a suspected rare/desirable OHC.DUCATI-Single, (although such over/mis-use of the name 'Diana', probably hasn't ever become quite so completely extremely-abused, yet).
Anyhow, the one/single-word name-term "Diana" (alone) has really never been a 'model-name' of any Duke-model ever produced by Ducati ! ...
__ There originally was a Duke-model with the model-name of 'Diana 250', which was a 4-speed road-bike. _ But it was merely a sportier-looking version of a '250 Monza' (with pretty-much just an ordinary Monza-motor).
However, it was after the 'Diana Mark III' (with a higher-powered engine) had begun to make a reputation for itself, that the name "Diana" -(short for: Diana Mark III) then-after came to be a well-known bike-name for a 'hot' DUCATI-Single. _ And-so since then, confusion has since developed between the 'Diana 250' & the 'Diana Mark-III' -(which is a completely different version of Duke-model than the Diana-250 !), and it's the Mark-III version that's THE particular hot-running Duke-model that the coined single-word/name-term "Diana" had actually become intended to represent, (rather than the ORIGINAL 'Diana 250') !
So when YOU-yourself merely state "Diana", I then can't be sure of WHICH Duke-model you're actually meaning to refer to.
And I'm left to wonder if you even know, yourself,, (whether your supposed "Daytona" is more like a 'Diana 250' or more like a Mark-III).
__ Can you tell me what the colors of the wire-leads are, within the black alt.cable (which exits the motor on the left-rear-top of the motor-case) ?



" I am presuming that it is a Daytona, but can only find workshop manuals which refer to the Monza, etc... "

____ I'm suspicious that if any Duke-models were sold in the U.S. with the name 'Daytona', that perhaps Berliner -(the somewhat shady importer), had done the renaming (of an existing Duke-model) on their own (after some kind of alteration had been added).
__ It would be quite interesting if some advertisement or flyer-paper on the Daytona-model could be found !



" The bike has been re bored at least once (74.8 mm piston) The piston is a flat top four ring rather than high crown high compression job. Is this right for the bike? The little I can find suggests that the Daytona was a sporting model, so I was wondering if it had a high comp. piston as standard. "

____ Since it's bore is now greater than 74.0mm, that makes it more difficult to be sure if it still has a stock-like piston...
The stock 'Diana 250' employed the same low-CR / 4-ring piston as the Monza, (8:1),, while the Mark-III version employed the 3-ring piston with high-CR, (10:1).
I really don't know what piston-model might've been stock for a Daytona-model's engine, but it stands to good-reason that a model named after a race-track would employ a higher performance piston.
__ More info needs to be known about your particular Duke, in order to know which parts are 'correct' -("right for the bike").


Hopeful-Cheers,
DCT-Bob

[Haggis]

Thanks Bob.

As far as I can tell the Daytona (UK) was the same as the Diana (US). I am not really looking for a book, just trying to get up to speed. I grew up with W/C Ducatis and regarded N/C as old school back then, so did not pay them much attention. I am rebuilding the Daytona and assumed that because it had a different model name there would be some material differences. It is useful to know about any differences as I plan the rebuild.

Thanks for the info on the piston. At least I know it has the right one. My concern there was that if it had the wrong piston for the carb settings / valve sizes I was going to have a hard time getting it to run properly once it was rebuilt.

The frame No. is DM250*82287*IGM1985OM. The engine No. is DM250 82519.

Thanks for your help. - This is definitely a Diana / Daytona 250 as opposed to a MkIII. At least now I can presume that the Monza spec is right for the engine.

Chris.

[DewCatTea-Bob]

" As far as I can tell the Daytona (UK) was the same as the Diana (US). "

____ By continuing to just state merely "Diana", (instead of the entire-NAME: 'Diana 250'), we now must assume that you're not meaning to be in reference to a Mark-III Duke-model, (even-though it's pretty-well understood that it's been established that the name-tern 'Diana' is MOST-often meant to specifically refer to a 'Diana Mark III').
__ Anyhow,, way-back in the '60s, I was told (by more than one unofficial source), that there was a 'hop-up kit' intended for the Diana-250, and also, that the Daytona-model was merely a Diana-250 fitted with the hop-up parts. ...
I'm not sure of exactly what-all the hop-up kit consisted of but, I'm quite sure it included a 27mm SSI-carb,, and likely also a megaphone, and perhaps also even a high-CR piston & wilder camshaft.
But all this stuff (in this paragraph*) is rather too vague to be very sure of.
(* For those who don't know what a 'paragraph' is these-days, this one begins with the word "Anyhow".)



" I am rebuilding the Daytona and assumed that because it had a different model name there would be some material differences. "

____ Just what exactly is your specific clue which leads you to determine that your particular Duke-model is actually a "Daytona" model, anyhow ? _ Along-with your purchase of the Duke, did you also receive official paper-work with that specific name stated on it, or what ?
__ Does your Duke-engine have a 24mm or 27mm Dellorto-carb ?



" Thanks for the info on the piston. At least I know it has the right one. My concern there was that if it had the wrong piston for the carb settings / valve sizes I was going to have a hard time getting it to run properly once it was rebuilt. "

____ Such changes within the engine really won't cause any significant differences in how the motor runs, anyhow.


" The engine No. is DM250 82519. "

____ Then it should be a 4-speeder.


" This is definitely a Diana / Daytona 250 as opposed to a MkIII. "

____ Then it ought to have just two yellow wire-leads within it's alt.cable.


Duke-Cheers,
-Bob

[jezza]

Mick Walker wrote in his book 'Ducati Singles' that the Diana 250 was marketed in the UK as the Daytona. If you can get hold of a copy of 'Ducati Gold Portfolio 1960-1973', it contains copies of several period road tests of the Daytona, which list it as having a 7.5 or 8:1 compression ratio. No mention is made of the size of the carburettor, although the Mick Walker book lists it as being 24mm.

[double diamond]

Chris,
According to Mick Walker’s book on Ducati singles, the UK market only received the Monza and Daytona 250cc models in the early 1960’s. Since you’re writing from Scotland, I imagine we’re referring here to UK models. The Daytona was sold in the US market as the Diana 250(note: not the 250 Diana MkIII which came later). The Daytona was eventually replaced in the UK by the Mach 1 in 1965(?), so the only early 1960’s 250cc street models you’re likely to encounter are the Monza and Daytona. The chassis of these two were, for the most part, identical with the exception of the wheel rims/spokes (M. Baruzzo rims/butted spokes on the Daytona) and the clip-ons/smooth fork crown/short headlight ears. The body parts were quite different, the tool/air filter boxes being the only pieces in common. Fenders, seat and tank were unique to the Daytona. The production engines were identical between the Monza and Daytona (including the UBF24BS carb) but I have seen various accounts of “race kit” components that the factory made available which may have included a high compression piston, camshaft and Dellorto SSI27A carburetor. I say “may have” because I’ve never seen any factory issued bulletins that describe these kit parts.I suspect these kit parts were basically 250 Diana MkIII spec parts. The original Monza/Daytona piston crown was not “flat” per-se, but had a modest crown to it with valve pockets. A true “flat” crown was only employed on the Sebring 350 i.e. no crown to speak of and very shallow valve pockets. Going by what you have described and the available models in the UK at the time, it would seem pretty evident that you have a Daytona. Obviously, if you read between the lines, one could easily make a Daytona out of a Monza with appropriate parts swapping. Basically this is what the factory did anyway, the two models distinguished only by how they were dressed. The “Tech” section of this website has a link to the early 4-speed parts catalog (http://www.motoscrubs.com/Ducati_D250-2 ... gue_CI.htm) for the USA model Diana. Your Daytona is identical to this model except for the decals on the tool boxes. Matt

[Eldert]

Hi Chris

you should try to get a hold of the Classic MotorCycle issue November 2004 .

it has a nice writeup about the Daytona and Diana

http://www.classicmagazines.co.uk/issue ... sue_page/9

http://www.classicmagazines.co.uk/issue ... /TCM200411

Eldert