State of piston/cylinder

[padly1995]

Hello,
My gy6 75cc scooter loosed about half of its power, and its max speed si around 70kmh.
Its also starting harder when its cold outside. After trying to change everthing besides the cylinder and piston i tooked those two off.
Do you thing they are bad?
piston 1.jpg
piston 2.jpg
cly1.jpg
cly2.jpg

And also exhaust valve is orange, do you know what could this be?

thank you for anwsers.