Well, those who say that there doesnt exist a Diagraphm kit for the FG 57 has really led us astray.
Here; I ordered this kit from hobbyplastic. It took just a few days and I had it in my hand.
The parts fits the FG-57 as well, so I have replaced mine now.
If you cannot read the small text, it says;
SAITO Genuine Engine Parts & Accessories.
Diagraphm Kit.
FG36
SAIG36-821-1
It angers me that those who should know, doesn't know.