Sorry for the jokesters.
A bike from '86' doesn't really need "restoring"... especially if it has been garage kept.
All it should really need is the fuel system checked out.
Drain any gas that has been in the tank (through the petcock).
If the petcock doesn't flow you will have to remove and clean it
Put in a half gallon of fresh fuel and let it sit for a day and slosh it around several times.
Drain that and don't re-use it.
Now follow the procedure listed below under "Troubleshooting and Tune-Up" to get it to run.
Sitting for that long means the carburetor probably needs a GOOD cleaning (inside).
If you don't want to do that , remove it and take it to a motorcycle shop and ask them to "soak it" in solvent and clean it for you.
After you get it running, ride it for 10 miles or so and then change the transmission oil.
(I believe a Kriedler has a gearbox)
Kriedler's are made in Germany and I believe them to be well made.