175/ 200 elite rear shocks

[JasonB]

Good Morning Motoscrubs,
I have a pair of early style rear shocks those I think came off 175/200 elite, was wondering if anyone has any info on how they come apart.

1956-Ducati-175-Sport-5-1.jpg

Regards
JasonB

[ajleone]

Are you looking to seel them, or just wanting info on a a rebuild ?
Tony

[JasonB]

Are you looking to seel them, or just wanting info on a a rebuild ?
Tony

Hi I am looking at rebuilding them, the picture of the bike is reference only.

Regards
JasonB

[ducwiz]

JasonB,

in the workshop manual http://minus.com/lE02OybuhG0jo you'll find a cross-sectional of a shock on page 38.
The spring and both shrouds are fixed by two half-rings (part no. 10), which are retained by a collar ring with angle section (part no.9). To get things apart you have to compress the spring together with the lower shroud while bracing the shock upside down on the bench, until the half-rings get released. Take them off their grooves in collar ring and shock body, and you are done.

Good luck Hans

p.s. The djvu file format can be viewed with the free Irfanview program (->irfanview.com), or with free DJVU plugins for your web browser (->caminova.net)

[ajleone]

Hi,
I have some pics of steps in taking the shocks apart. It is pretty simple really.

http://www.coolitalianbikes.com/ducatidiana

Tony

[JimF]

Tony,

I love your website and the videos.

Could you tell me what the differences are in the two tanks where you've pictured them side-by-side? It's like the "where's Waldo" thing, but in my case I can't spot the difference...


Jim

[ajleone]

Jim,
These are 2 4.5 Lt tanks, for Diana 250 4-speed bikes. One tank has the contour on the bottom to clear SSI carb (for Diana 250 Mark 3) and the other does not have the contour so it will only work with w a UB carb (as on the Diana 250 and GT 250's.
Tony

[JimF]

Hi Tony,

Both my M1 and my spare M1 tank have a more scalloped and very rough looking indent for the carb top, the same as I see on this picture which I stole off of eBay:

M1_M3_tank_bottom.jpg

That's why I could not reconcile the differences between the tank bottom shapes in my mind.


Here's my tank bottom from my 250 that came with a 5-speed gearbox and no AAU:

250_tank_bottom.jpg

What clues does this tank offer about my 250?

[ajleone]

Jim,
My tanks line-up with the tank pictures and what you have, I think.

Here is my Mach 1/Mark 3 4.2 Lt tank (silver) and a Diana 250/GT 250 2.4 Lt tank (blue. The shape of the contour/cutout on the bottom is a different design between the 4.2 and 4.5 tanks, or at least that what appears to be the case. I have another 4.5 Lt tank that does not have the contour on the carb side, and this tank came on my 4-speed 250 Diana.

So, I am not sure what the conclusion is. But it is interesting that Ducati changed approaches to their tank design. I am now wondering what the reason was - if the Mach 1 has a 29mm SSI and the older Diana 250 Mark 3 had the 27mm SSI would there be a need to add the scallop to 4.2 Lt tanks ?
Tony

[JimF]

I apologize that I hijacked this thread off-topic, but I have one more question/comment while we are off on this tangent.

If I am a higher-up at Ducati in the 1960s and some guy says to me "we fitted the new Mach 1 engine but when we put the tank on it hits the carb..." I have to think having a new intake manifold with a few degrees of bend made is going to be cheaper fix than having the tank maker build a cavity into the fuel tanks.

Maybe there is a performance reason why bending the intake manifold was not done, or maybe it was just cheaper just to have the tanks modified.

Any thoughts?