Ducati 250 mk3 piston id

[Scottish888]

Hi,

Ducati piston.jpg

Can anyone tell me what these numbers stamped on top of the piston mean?

784 -65075/3

Bike is a Ducati 250 mk3 1974.
The previous owner said he had never carried out any work on the bike, no idea about the first owner, mileage is under 7000, I think the previous owner never bothered to check the oil level as it had a minimum amount.

[Eldert]

looks like the std 74 mm piston to me

Eldert

[Scottish888]

Thanks Eldert,

The engine has very little compression yet the bore and piston did not look so bad when I removed the cylinder, no significant wear ridges, rings were free I am hoping a piston clean up and a fresh set of rings could make a difference.

Regards

[ducwiz]

Have you checked valves and seats ? And have you measured your piston and cylinder bore diameters?

[Scottish888]

Hi Ducwiz,

I did not check the bore yet, just a quick visual but no wear ridges near the top.
I poured fuel inside the head combustion chamber and it held with only a little dampness around one of the valves, so not too bad there.
Will measure piston/bore accurately when I do the crank.
About the piston numbers, they don't match any given in the Haynes manual. I am assuming like Elders says that it is the original piston but maybe not.
It looks like it is a B grade piston as there is a B stamped on it, will need to measure it with calipers.
Any idea what the A or B grade means?

Regards,

[Eldert]

this is what A , b or C means

A , Band C

Eldert

001.jpg

[Scottish888]

Thank you Eldert