125 Sport cylinder?

[LexH]

The cylinder on the left was sold to me as a Ducati 125 Sport cylinder. It appears it may not be. The base flange is completely different and will not fit my 125 Sport crankcase without significant welding and machining modification. Aside from the different base flange it appears to be the same as 125 Sport. Original 125 Sport cylinder on the right, with correct base gasket overlaid on both. The cylinder came with a piston which looks at first glance like a 125 Sport piston but on closer inspection has a 16.25mm gudgeon pin hole vs. 16.00mm for 125 Sport. Anyone have any idea where this cylinder came from?
Cheers, Lex

[Jon Pegler]

The cylinder on the LHS of the photo showing both barrels looks to be from one of the late 125 Scramblers, built up on the 5-speed Spanish narrowcase bottom end, hence it has the base gasket with the more barrel-shape rather than the more square shape gasket.
I don't think you will easily be able to use that cylinder in an Italian or Spanish 4-speed bottom end, without quite extensive modifications.
It's quite a rare item though.

Jon