This is my 250CC scooter on back of my "gasser". Scooters are harder to carry than motorcycles. I customized my existing hitch by adding two combo bars (receivers) and making C channel rack and ramp.
No rocking and rolling ever and it has been to Alaska and back to NY.
In this picture, we were in Ninilchik Alaska.
$220 total including having all welding done at the local trailer shop. I designed and precut all steel parts. Instead of the light bar in the center receiver I can still install one of those Hitch Hauler trays. at the same time as hauling the scooter (or a motorcycle). The light bar is just one of those bed extenders used on pickups to carry long items. I added lights because it feels safer. The Hitch Hauler tray has lights I add on when needed.
Gasser frames are weak at the rear. My MH is 14 feet behind the rear axle! The frame has been extended by 6 feet with some what I call weak reinforcement. Still that 14 feet is an awful lot of leverage. The hitch is rated for 500 lbs. So with my additional weight for the rack and my scooter I'm just under that limit. I used to have a rear weight issue with my MH manufacturer but we resolved that problem. It had nothing to do with the scooter and rack though what I did wasn't helping matters. Now all is fine.
I forgot to mention. While travelling, since our fresh water is at the very rear of the coach, I will only carry 1/3 to 1/2 of the water capacity. It helps offset the scooter/rack weight. We never had any problem finding water to top off the tank. No matter where we stayed be it a CG or booning. (I know, I've never been in a real desert).