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Hello all together,

a happy new year...

I have bought on ebay a lot parts - the seller means a complete bike, a Diana Mark 3 - but i miss some parts.
After the first look in the boxes i´m a little bit confused ....
Please help me to identify this bike.

1. Frame Number DM250*82034*IGM1896-OM

- Suspension for the swingarm
- Battery tray
- attachment for fender on the rear frame Loop



- the strange mount with the two holes



- whats that near the steering head?


2. tank

- it is an early Diana tank with the symmetric welds
- but this hole in mach1 style? it looks professionally made



3. steering head

- under the Mounts for the fork tubes are this parts welded?


4. parts
- i found the original rear sets
- handlebars etc. with stamping tomaselli (Matador ?)
- 7-fin hubs
- a 180 km/h speedo from CEV
- missing carburetor, front fork, rear Shocks and a lot of small parts


5. engine
- number DM250 (left housing) 82411 (right housing)
- Rockers with screws not with shims
- helical teeth coupling

What have i bought?????????????????

Karsten

KarstenH wrote: What have i bought?????????????????

Hi Karsten

(Ok, this should be fun … )

To start, I am going to assume that all the bits you have go together, i.e. it’s not just a mish-mash of spare parts! So:

1. It’s NOT a Diana Mark 3.

Why? Because, strictly speaking, the 'Diana Mark 3' was an American model ONLY, and American bikes did not have a frame number. Which your bike does have.

2. Therefore it is a European specification bike. Which means it’s either:
a) A 4-speed Diana from 1961-1964

b) A 5-speed Mark 3 from 1964-1967.

So first question: How many gears does it have?

The engine number prefix of DM250 should be correct for a 4-speed. If it is indeed a 4-speed, then comparing your engine number (82411) with what is on the register at Steve Allen’s site, it is probably a 1962 because there you find engine numbers 82175, 82261 and 82572, all from 1962. Additionally, it would appear from the register that 1963 bikes have 83*** numbers.

However that doesn't explain your tank with the carb cut-out. Nor do I understand your frame homologation number, IGM1896-OM. That doesn't seem to correspond with anything I can find ... for the moment. (The normal n/c frame homolgation is IGM 1985-OM).

If it is a 5 speed:
a) It will be from before 1966 because that’s when the 7-rib hubs stopped.
b) And it will most probably be from 1965, because that was when the Mark 3 got the bigger carb and therefore the tank cut-out.

However:
Ian Falloon says that the Mark 3 got a new engine number prefix, DM 250 M3. So that doesn’t fit.
He also says that it used shims for the valve adjustment. And that is what the parts book and the owner’s manual says too. So that doesn’t fit either.

HTH

Craig

[quote= KarstenH ...
" I have bought on ebay
- the seller means a
Diana Mark 3
Please help me to identify this bike. "

____ It is-not a "Mark 3" !
But it indeed is a "Diana" ! _ A 1962 'Diana 250' model, to be more specific, (which is most definitely a 4-speed model).
Also, it's fairly expected to be a model made for either the Netherlands or a neighboring country. _ What country did you find it residing in ?



" - Suspension for the swingarm
- Battery tray
- attachment for fender on the rear frame Loop
- the strange mount with the two holes
- whats that near the steering head? "

____ I've never seen a stock frame with any of those rather strange features.
I suspect all those added-on features & others were custom-welded by a well-experienced & carefully-meticulous master-welder.
The added piece seen on the steering-stop brace, looks to have been intended for a steering-lock setup, (probably made to simply accept a padlock).



" tank
- but this hole in mach1 style? "

____ It may-not be the original Diana-tank,, but otherwise, it was probably intended for being matched-up along-with a 27mm SSI-carb.



" engine
- Rockers with screws not with shims "

____ Just as is expected for a 'Diana 250', which employed the same cyl.head* as the Monza, (* with 26.5mm intake-port).



" What have i bought????????????????? "

____ Quite apparently a very unique & pretty-nice Duke-project !


Duke-Cheers,
-Bob

Thank you Craig and Bob,

i agree with you in the age of this bike.

Some new informations
- intake Diameter is 29 mm
- big valves ?

- big Piston


- 4-speed



- Generator


Yesterday evening i had googled - i found one other bike with this Frame on Dusati MS Forum.
look for "Ducati Mach 1/s" it´s a red racer
The early Mach 1/s should be a series close bike for hobby racers.
Could it be?

Karsten

The frame is a modified Diana/Monza frame. Mods include: a completely revised battery tray. The original tray has been removed and replaced. Outboard swingarm axle mount which was a common racing modification. Gusset in front of the front seat mounting bolt. The addition to the steering stop looks like some sort of steering lock but this mod would eliminate the steering damper. Does the lower fork clamp have some sort of accommodation that lines up with this mod to the frame? There are a few other extra tabs welded on the frame. The tool box/air filter housing mounts indicate Diana/Monza. The early Diana did not have rearsets and with the mods to the frame at the swingarm pivot you probably have an accessory foot control arrangement. The gas tank has been modified to clear a larger carb or to allow better access. This is not a factory Mark 3 tank mod. The rings welded on the lower fork clamp appear to be added so rubber accordion boots can be employed on the front fork instead of the standard metal shrouds. The combustion chamber looks standard, probably a 37mm intake valve. The piston is a forged 3-ring component, which would not have been standard on a 1962 Diana. Maybe the mysterious “kit” piston or simply a piston from a later version Mach 1 or some such. The valve cutouts are much larger than necessary to accommodate the valves in the head that is shown. The crankshaft appears to be a Mark 3 component. You’re not showing all of the transmission but it appears to be a 5-speed: there are three shift forks in there. Looks like the first gear on the driven shaft isn’t installed; it should ride on rollers in the bearing race in the left center case and it’s drive gear should be machined on to the input (clutch) shaft. How you got a 5-speed in 82xxx series cases is a puzzle but it could be an early production 5-speed. Something about that transmission looks odd to me. You’ll have to remove it from the cases and post a picture of the entire assembly. No surprises with the alternator; it has been re-wired and two rivets holding the flange to the flywheel are broken off. Doubt it’s a M1S. The frame you have has Diana/Monza hardware and the M1S has basically a Mach 1 frame. But the welds and fabrication on the frame looks like factory work, although I’v e never seen anything like it. The engine is certainly not M1S. Matt

Hi Karsten (german/deutsch?),

this bike definitely has nothing to do with a Mach1/S. Compare your frame with those being visible on http://www.ducati.ms/forums/14-vintage/66536-250-mach1s-questions.html. Besides, the Mach1/S came from Ducati's race shop, should have a no. starting with SCD (scuderia corsa Ducati). It should furthermore have a cylinder head with exhaust studs, not a big finned nut/thread.
In my opinion your bike is a conglomerate from different models, with modifications made by owner(s).

cheers Hans

[quote= KarstenH ...
" - intake Diameter is 29 mm "

____ If exactly 29.0mm (+/- .25mm), then it's been 'ported-out'. _ However if actually 29.5mm (+/- .2mm), then the cyl.head must likely be a Mach-I type.
However if actually 28.5mm (+/- .2mm), then it's rather most likely a Scr/Mark-III cyl.head.
____ Since the cyl.head is certainly not stock 'Diana 250' issue, it's particular camshaft is of much interest now !



" - big valves ? "

____ The standard 'large-valve' sizes are 40/36mm, (which they appear [to me] to possibly be).



" - big Piston "

____ You'll have-to measure it's actual diameter to determine that for sure.
__ That piston appears to be a 9.8:1 Mach-I type piston, (as also first employed within the 1965 Mark-3 model). _ Next most likely piston-model, is a 9.5:1 w-c.250 version.



" - 4-speed
gearbox inside "

____ Your posted pic.shot of the trans leaves a good bit to be desired !
Your iPhone-camera seems to center it's view-shots considerably towards the left-side of your intended view-point.
__ With your camera-shots set for such extremely high pixelation-density, your view-distance really doesn't need to be so close-up (as it seems you chose to more-so do especially for your transmission picture).
So how-about another pic-shot of the trans from further back, so we can then see everything ?
__ Also, it's of certain interest to learn exactly how many teeth are on each of the gears of the 1st.gear-pair*, (if not on all the gear-pairs) !
(* The stock/std.production 4-speed trans 1st.gear has 44/16t.)



" - Generator "

____ That 6-pole alt.model is-not consistent with an Italian-made pre-1964 4-speed motor. _ A 'Diana 250' should've been factory-stock rather with a 4-pole alt.version.
____ Hopefully one of our West Europe members can tell us if your mystery-Duke (compilation/bitsa) might possibly rather be a Mototrans-version, (whole or in part).



____ Most-all posted pix appear too dark/dim on my PC.monitor to properly see well,, so for any others who might also experience the same deficiency, I've added brightened-up pic.versions.
(It would be nice to learn if anyone-else at all, also sees any worthwhile pic.lighting improvement, [as I do !].)


Duke-Cheers,
-Bob

Thank you Bob for the better Pictures.

With the gearbox i have a Problem - how can i split the case withaout brute force?
I want no destroy anything.
All screws are loosen, only the two gearshafts are inside the cases.

Karsten

If all the center case screws have been removed as well as the two bolts to the front and rear of the cylinder opening and you are having difficulty separating the cases, the cases are probably stuck together due to 1) gasket sealer on the center case gasket and 2) tight fitting dowel pins. You should be able to tap on the transmission shafts from the left side and separate the cases. Use a soft mallet (rubber, copper) or hold a block of hardwood betwen the shaft end and the mallet. You should also tap on the shift selector drum while separating the cases so that the entire transmission stays in the right side case. The dowel pins can be very tight if they're rusty or have been glued in place with hardening gasket sealer such as permatex. Matt

Hello Bob,

my inlet Diameter is 29,2 mm +/-

Valve sizes are 39,4/36 mm

Ill try to split it today, then i can report the number of teeth from every gear.

Thank you Matt, the dowel pins are very tight - the undersite splits (5 mm) but near the head is no movement.
I think i need some other Tools and then it splits.

Ive got it,


Number of teeth:
17/22/26/29/31
30/32/35/39

Karsten