New camshaft

Today in the mail I recieved a new hot camshaft for the 90 that I had won on ebay. Didn't have much info when I bought it about timing and lift, So I was hoping it would be different from the hotcam I allready had. And I was lucky.
From left ro right: original S90 cam, hotcam #1, hotcam #2




More lift and duration, looking forward to building the 90 engine again, it has been on a bit of a standstill.
The racers needed work and I am making new handlebars for my moped, time is scrace during racing season.

unknown piston

My dad is building an 85cc race engine based on an XR75 (post 1976), it is for a friend who will race it at a moped racing club.
This guy brought over a lot of parts to build with, including a big bore piston.
I like this piston, for the 50mm bore that is was originally built for, this one is a 50,75mm bore, 3rd oversize.
This has a 13mm piston pin, just like xr75.
But this piston didn't have any original box, or any markings, so I don't know what it is.

Can you help me identify this piston????

50mm standard bore
13mm piston pin
And very distinctive valve indentations.
But I can't even be sure it is honda, it might be something else.
If you have any idea what this is, please send me an email.