As I have been asked on another forum what difference there is with a stock 750 CB , here is some more information
On their first 950cc engine Japauto used an OEM engine block together with a rebored OEM cylinder block.
That was enough to win the Bol d'Or in 1972 and 1973 but was a little too "crude" for road use with too much oil leaks.
So in 1974 they started working on a carefully rebored engine block and a new cylinder block casting made by JPX with special pistons by Bretille (see second photo)
The engine became both powerful ( 85/100hp for road use depending on the exhaust and carbs) & reliable.
On this photo you can see the original Honda CB cylinder block ( center) the first 950 SS cylinder block ( left) and the 1000 VX cylinder block (right) as well as the three corresponding pistons.
The engine look is very different with the JPX cylinder block