Hi,
The following MZ special tools are required to reinstall/set the camshafts. I've done this work myself and it's not too difficult a job.
It's also best if you put new gaskets on the chain tensioner and valve cover. It goes without saying that you'll need a torque wrench as well.
Crankshaft locking bolt 8999200000
Camshaft adjust tool 8999206000
All parts available from Grahams motorcycles in Taunton, Somerset (parts may take a while to arrive because of recent change in management at MZ in Germany)
Here is a zip file of the RT125 manual
HTH,
David