MAKING CHANGES IN A 24 HORAS

[DewCatTea-Bob]

" a normal 175 / 200 cc headcasting is flat and smooth on top . this one is a little arched and has finning "

____ Thanks for the picture of that head, Eldert!
I've never seen a head exactly like that one! _ It looks to be a 250/350-casting with the old SQUARE bolt-pattern of the 175/200 engines! , Interesting!
__ As for the old 200-heads, I've never seen a 200-head that did not have those fins on top! _ However, the fins were always completely straight-across & flat -(without that arched-bulge in the center, as the newest heads all have).
____ Where did you get a 24Horas-250 from, Eldert, was that model imported to your counrty from Spain?
Since that head has the old 175/200 bolt-pattern, I would then expect it to have been attached to the older-type of motor-casings which were designed for the 4-speed trans. _ Do you know if the long-stroke 250 models were made with both 4 & 5 speed transmissions?
Cuz if they had been, then I'd expect that JPALOMO has the newer 5-speed 24Horas model with the regular 250/350 bolt-pattern, -(as I assume his Strada also must have).

____ I hope that there are others of us who also find this thread of interest, (at least enough to read)!
__ Please tell us more about your project, JPALOMO!!


DUKE-Cheers,
-Bob

[Eldert]

Hi Bob
yes you are correct about the 175 / 200 finning on the head
as far as i know all the 24 Horas where narrowcase and 5speeders
the 300 cc widecase engines where only 256 cc ( 66 mm bore and 75 mm stroke )

here a link to mototrans engine and model history . in spanish sorry about that

http://www.ducati-sud-belgio.be/1.0/?na ... article=41

the narrowcase 250 road had the same bore and stroke (69 X 66 ) as the 24 Horas and had a 5 speed cluster to
i owned 2 but sold them . i have only one cilinderhead left ( empty )

Eldert

[JPALOMO]

Hi boys: Yesterday I answer you but Idon't know wy my answer was lost. The story started when I bought the 24 horas, it exist only with narrowcase, with a broken connecting and with a damage camshaft. Itake contact with Mariano Sanchez a reputated mechanic with a shop in Madrid, he explain to me the way to repair the machine and how to put an oil radiator. This was the firs reparation and it was the begining of some modifications.
1Stage: Inox megaphone with fiberglass mufler home and hand made, Amal 30 mm carb, before 27 mm
2 Stage: Rear shock sorbers tipe De Carbon with a separate gas chamber, seat from a Vento Mototrans, a beautiful 350 widecase, new pedals home made
3 Stage: Crakshaft 57.8, before 66, and piston 76, before 69. For this big change It was neccesary to reposition the boltholes
buy a strada 250 head and cilinder (74 mm) and rebore to 76 mm.
Many problems with the piston touching the head, I broke the holes and I must tu rebuilt with helicoil.
4 Stage: I will tell you tomorrow, I must go to sleep, dont worry I will prepare pictures.

[JPALOMO]

http://perso.wanadoo.es/kombo/Imagenes/24horasjulio.jpg h this is a link with a spanish page

[JPALOMO]

Here a picture, working in the street

[DewCatTea-Bob]

_____ Thanks for that link Eldert! ...

By Eldert: "as far as i know all the 24 Horas where narrowcase and 5speeders" ...

___ I had known that MotoTrans had done some unusual production changes with DUCATI-motors, which Ducati in Italy never did but, I have not realized how great were the extent of their changes! _ I did learn that MotoTrans had continued-on to produce the older narrow-case Ducati motor-designs but, I sure did not think that they would've troubled to somehow find a way to put a 5-speed-trans into them!
Now I really wonder if they came-up with a different 5-speed trans to fit within the old 4-speed type motorcases, or, if they reworked & recast those old-style motorcases to accept the regular NarrowCase 5-speed trans !?? _ (Or perhaps for some very strange reason, they chose to use the old SQUARE bolt-pattern on the newer 5-speed (narrow-case) motor-cases?) Either way, it seems to me to be an inexplicable endeavor. _ The only thing I can think of as to why MotoTrans would go to the expense of doing such, is cuz perhaps it was even more expensive to purchase the rights to produce Ducati's own newer designs (during the times).
__ Sure wish I could've examined all the different models of DUCATI-based motors that MotoTrans ever produced!


By Eldert: "the 300 cc widecase engines where only 256 cc ( 66 mm bore and 75 mm stroke )" ...

___ Wow, I don't recall ever learning of such an extra-undersquare DUCATI-engine as that before. _ It seems to me that MotoTrans would've used (at least) their 69mm-bore with that (350) stroke (to get 280cc)... As a 71mm bore would've been needed with that 75mm-stroke, to get a full 297cc, "300" motor!
Also, I find it very quite odd that MotoTrans would do such an under-square bore & stroke combo, after getting the rights to produce Ducati's WideCase motors! _ The only thing I can think of for producing the equivalent of a 350 with a bore-size that's reduced to 1mm less than a standard 200-engine,, is to create a motor that has as much low-end torque as possible, yet still be within a displacement-catagory for road-insurance purposes.

____ Concerning Ducati 300-motors (of Italy), I had heard of only one story on the subject.....
The story was told to me about 3-years afterwords, back when it was expected that a newer design (then called the "wide-deck") was to be imported into the U.S. in 1967.
I was told not to hold my breath waiting for that newer design to ever actually arrive because, the once expected 300s (amongst other once expected models in the past), never did show-up either!
__ The story was that back around 1962, Berliner -(the U.S.-importer), had badly wanted to grab a-piece-of-the-pie of Honda's 300-market which was quite sizable (from 1960-on) compared to Berliner's market for all DUCATIs! _ So Berliner had convinced Ducati to start producing a 5-speed '300' sometime in 1963, so that they could be introduced (soon enough at least) as 1964-models.
__ The first order (as the story went), was for a '300-GT', to compete with Honda's 300-Dream touring-cycle -(back in those days, we called em "cycles", not 'bikes'). _ Soon followed by 300cc Scramblers, to compete (for the market) with Honda's '305-Scrambler'.
While the 300-Scrambler model was to have a close-ratio 5-speed trans with very low-gearing, 19" wheels, and fitted with Dell'Orto 27mm SSI carbs, and a small gas-tank, and no battery,, the GT was to have very high gearing with 18" wheels & a smaller 24mm Dell'Orto (for best fuel-milage), and a big 5-gallon GT-tank, for extended range.
__ It was later learned that the reason that the 300-motors never came to be, was largely due to Dr.T not agreeing to (once again) increase the displacement of his original motor-design (which had been intended for only 175CCs).
When Berliner finally realized that the 300s were not going to become available by 1964, Berliner realized the trend towards larger displacement and told Ducati to skip the 300 and go for a '350' instead, and also twisted their arm -(demanded of Ducati) to go over Dr.T's head to come-up with a '350' asap. _ So for 1965, the 350-Sebring finally came-out (mounted with the small carbs which were no doubt originally ordered for the 300GT) !
To please Beliner's demands, all Ducati basically had to do was make the 300GT-motor's cylinder-jug 4.5mm taller and increase it's stroke from 66 to 75mm. _ I have no good explanation as to why they didn't go for an even 76mm! _ Perhaps Ducati wanted to maintain their reputation of being for the 'over-square' school-of-thought (that was considered more modern back then).
__ I am quite confident that the 300 (narrow-case) had indeed been in the works, cuz I once saw a picture of a cylinder-jug for one! ... A fellow in Italy had it, and it had 8 fins (like a 250's), with a base-flange about 4mm thicker than any 250-jug's.
(If that fellow in Italy reads this, please post a picture of that extra-tall 8-finned cylinder that you have!)


DukeCheers,
-Bob

[Eldert]

Hi Bob
the only 300 cc engines i know of where one offs for 24 hour races in Spain .
i had a article about then in a Italian magazine but someone borrowed it and that was
the last i seen of that article ( i will try to get it back )

Frankie Scurria build the first 350 himself in the winter of 62 /63
in California the engine was square at 76 x 76 . Alan Dalo from ARD magnetos build the crank for him
the only problem was the briddle cast iron primary drive kept losing teeth

later Frankie send his drawings to the factory and the 350 Sebring was made

Eldert

[JPALOMO]

Here again, I saw that the picture thos'nt come cause are to big, how can I reduce the size?

[Pete]

One way to reduce image size is to go here http://www.microsoft.com/windowsxp/Downloads/powertoys/Xppowertoys.mspx and download the image resizer. After you download and install, just right click on your picture and pick the resize image option. You can then pick the size you want. It will then save a resized copy in the same folder as the original. I use the small size a lot.

Pete

[JPALOMO]

THANKYOU PETE, now some pictures, I promise you that when Iprepare all pictures in order I will put it in the page