I did the trip yesterday with my 2009 Suzuki V-Strom DL650 (on Pirelli Scorpion trail tires= road tires).
In fact only half of it (about 82km) is fast, but curvy high quality macadam (gravel road) that winds through spruce pine forest, almost without any sign of human presence. The other half is curvy asphalt (more tight, than fast corners, sometimes narrow) with low to no trafic.
I am local, from Ljubljana, but I was surprised, that author found this fantastic track so close to my home.
In total it took me a bit less than 4hours without only a short stop for gas.
Good macadam forest trail for big enduro bikes.