Mornin to Norway,
mornin Asgeir!
Sepp Koch is professionally working on TR1 parts:
https://www.tr1.de/tr1/offerings/parts_sepp.htm
contact him, he knows.
or:
Heinze Rosner:
Almost all TR1 parts can be ordered from Heinze Rosner.
You'll find his address in the drivers section.
In case you are still encountering problems finding Tr1 pistons an drods, contact me,
I'll see what I can do.
cheers,
Klaus