I carry all my bikes up to my 790, so ~200kg, on a rack I made which is mounted to the bumper (hence also towbar-bolts) of my Landcruiser bakkie.
It mounts with 6 large bolts: 4 on the towbar-group and 1 each on the side to the bumper i.e ladderframe of the vehicle for stabilization.
I know it will take an even heavier bike but a BM boxer will not fit width-wise.
The bike rides on/off via a ramp with me alone doing this, I need no help, and I clamp the wheels via turnbuckles.
Then a few tiedowns do the rest to stabilize the suspension preventing it 'bouncing' on the springs.
I made this rack myself hence know it is seriously strong enough, and the inspiration was the Xramp principle... but this system I think is way too flimsy for anything bigger/heavier than a plastic.
A cruiser is also a big-enough vehicle for doing this: a plastic loaded I don't feel, neither my 701, but the 790 I do notice a little, especially offroad.
I've been asked quite a few times already if I won't make some of these racks due to the simplicity of loading as well as fastening the bike!
Answer's No, pls make your own - look at an Xramp, make it stronger AND attach it to the ladderframe (sides!) of the bakkie so as to prevent longitudinal rotation (twist). And yes, a bakkie would be your minimum, forget any cars.
After I made it I stopped at a few roadblocks where several officers were present, showed them this contraption on the back of my bumper (it makes the vehicle some 75 cm's longer) and asked if this is going to be a problem legal wise.
NO was the unanimous answer I got - and do note that the wheels stick out a bit either side - they all thought this was perfectly legas plus a nice thing to do.
I've 'doubled' the lights & numberplate etc, plus a plethora of reflectors make it a christmastree at night when headlights fall on it.
Because the cruiser is rather high I look over the bike from my rearview mirror, no problems in this regard.
Works super, can recommend it!