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Looking forward to talking about my project with all the other Ducati vintage single detectives out there! I bought this bike in 1990 as a complete basket case for $175 from somebody that was given it in exchange for doing some yard work lol. It came with a 1966 NJ tag and I believe that was the last year it was ridden.
It really appears to be a 1963 Diana Mark 3. The forks are stamped 1963. The original foil is stamped 250 D 3 and the number on the foil matches the engine number DM 250 84597. It has the short front fender, the magneto, the veglia tach, the clip-ons, the exposed spring rear shocks, no sidecovers, etc etc. But it also had weird stuff in the box – the engine had a 24mm carb on it (not 27mm) and the rear fender had a lot of holes in it that looked factory drilled, I also had two different rear taillights with larger lights and license holders which makes no sense for a 1963 Mark 3 which should have the small taillight and minimum holes in the rear fender. Also – I had two different type of fuel petcocks that both had the smaller 5mm nipple outlets.
So I “think” I have a 1963 Mark 3 that I am bolting together but I am not sure. Unfortunately the rims and spokes were a total mess when I got the bike, they had been sandblasted and painted matte silver but the rims were deeply pitted. Like a total idiot, I tossed them years ago and sent the hubs to Bucchanans and they built up new wheels with Excel rims. It does seem to have the original saddle – spring frame, cover and the previous owner even made a new cover creating a tenplate from the original cover that had the rivet holes and rear section where the Giuliari tag was affixed.
The engine was recently done by Rich at Desmo Pro and he added a 29mm carb and slick custom megaphone. The paint work is done and I had the frame powder coated in a color that was as close as I could find given the limited color selection they gave me. It’s far from perfect but durable at least.
Instead of posting a ton of photos, here is a link to many of photos, https://link.shutterfly.com/MJF9QrC973

Appreciate any thoughts and guidance you all can offer in helping me to finish the resto.
Pete

Very nice. For $175 you got a hell of a deal!

Is it a 4-speed or 5? And which side is the DM250 stamped on?

I've got 82480 on mine and it's 4-speed. I've got no idea if mine is a real Diana or not. I picked it up at a swap meet years ago.

Yeah it definitely was a good deal 30 years ago and it was a bunch of parts. The DM250 stamp is on the right side of the case if you were sitting on the bike looking down. It is a 4 speed.

I am just guessing that one of the original owners decided to put the bike on the street and did some mods. I do think it is a Mark 3 - does anyone know if the "250 D 3" stamp on the foil indicates that? Aside from the equipment the bike has and the engine serial number?



But the items that came with the bike that has me confused are:

1. The taillights - neither of which are correct to a 1963 Mark 3
2. The rear fender which has many more holes than a 1963 Mark 3 rear fender should have and they look almost factory perfect
3. The carb was a 24mm not a 27mm and yet the fuel tank has the asymmetrical cutout which supposedly allows the larger carb
4. the 2 sets of fuel petcocks that the owner gave me have 5mm outlets (I don't know if the Mark 3 came with these or larger 8mm outlets that match the larger carb inlets)
5. Otherwise everything looks Mark 3. The small Scrambler front fender, the clip ons, center mounted Veglia, Magneto ignition, rear shocks with exposed springs, etc etc

Going by what you have described, I would say you have a Diana Mark III. The 24mm carb (UBF24) is from Monza. A Mark III should have a SSI27A. Your frame should have no attachments for tool/air filter boxes or horn. The underside of the tank should be asymmetrical but should not be dented to clear the carb. That type of tank was employed on the later Mark 3 with a SSI29D carburetor. The Mark 3 tank was also smaller capacity. The foil with “250 D 3” is another indicator. Early Diana Mark III’s typically had a small round lens taillight but I have seen them with the rectangle lens CEV with alloy housing. Does the taillight bracket have an on/off switch? If it has the center mount tach bracket, it should also have a “pan” headlight assembly with Aprilia rim and lens. Should have the Campagnolo 7 fin hubs, smooth fork crown without handlebar mounts and lever perches should be brazed to the clip-on bars. Rather than describing every detail, perhaps you can post more pictures for identification?

Matt

Thanks Matt -

I did provide a link to like 50 pictures here https://link.shutterfly.com/MJF9QrC973

Here is the underside of the tank


Pan headlight


These were the taillights I got with the bike, the rectangular one looks too new and has no switch, the circular one looks period correct but is too large:




Not sure what welds I am looking for on the clip ons but here they are



Rear shocks with exposed springs



Front wheel hubs (I tossed the original rims like a moron years ago cause they were rotted/pitted badly and had new wheels built on excel rims



Thanks for your help. It's the small carb it came with, and the rear taillights that have me scratching my head. Everything else looks legit Mark 3

Pete

The tank is Diana Mk III. Nice color match. I do not recognize the rectangle taillight. The other round taillight is a CEV 931 which was a common Ducati item but not on a model as early as yours. There is an Italian company that makes a very nice replica of the small Diana Mk III taillight that you might consider. Not much one can do with rust pitted rims so don’t feel too bad about that. The original M. Barruzzo rims are difficult to procure at any price, let alone the butted spokes. The clipons are the straight clamp type typical of 175/200cc sporting models (rather than the barrel clamp I would expect) but your Diana is so early those clipons could be original. The small ball levers certainly are. The clipons should be chrome plated. Headlight and switch look correct as are the shocks but they should have plastic shrouds under the springs to protect the damper shafts. The 24mm carb could easily have been an owner replacement for any number of reasons. What is the size of the intake port at the mounting flange?

Matt

Thanks for the info - the intake port at the flange is 28 or 29mm diameter

On the rear shocks are there rebuild kits? Also should the rear shock springs be chrome? Are there good aftermarket shocks available?

I had a feeling the clip ons should be chrome, looked like they were painted over black. I will send them to get chromed.

The previous owner did some interesting things many years ago, like putting this rubber dipped coating on the shift lever and the kick start level:



I guess I will look to buy one of the small, correct taillights but unfortunately the rear fender will then have too many holes and its been freshly painted which is a bummer

Ducativintagestore.com is the only place I can think of that might have shock rebuild kits. The springs should be chrome. Hagon shocks are the most period aftermarket shocks available. Koni’s would be appropriate to if you found a decent used set.

With a 28mm intake port, obviously a 24mm carb is a mismatch. A Diana Mark III should have a Del’lorto SSI 27A “green tag” carburetor. They turn up occasionally. The SSI 27D was installed on later production scramblers.

The rubber coating on shift and kickstart levers might be to cover pitted chrome. Or you might get lucky and find well preserved original chrome underneath.

Matt