I am not finding much info on this tiller. I did see one for sale in Bulgaria, but the weight was not listed. It did tell me that it is a 60” model. 
Looking at your pictures, with those heavy furrowers on the back, I would have to estimate it to weigh 400kg. Give or take 100kg. 
It’s just a guess, but the construction does not appear to be very heavy, but I can not see the underside, and the size of the rotor and tines could vary by quite a lot. 
Sorry we couldn’t be more help, this model does not appear to have had many sold in the US. 
Hopefully this translates well.