I have the owner's manual for my B7100D, and it lists the 3-point lift capacity as 400 kilos. That would be 880 lbs. The dealer said that all the B7100 tractors are rated the same.
BTW, since the tractor weighs 1000 lbs., it's pretty easy to lift the front wheels if you don't have some extra front weight. You should have seen the first time I lifted my 60" Land Pride rear mount mower! (At least it has stearing brakes ;-)