Not sure what you mean by "little motorbike." I use a 125cc motorscooter (commuter vehicle for a couple years) but at about 250 pounds, it is not something I can throw around.
You might find 50cc scooters a bit under 200 pounds, and 150-200 was typical for mopeds. Still a lot to be tossing about, but can be pushed up a ramp.
When you get smaller, you start running into "must be street-legal, licensed and insured" to use on roads in public campgrounds, but if you go electric, particularly electric bicycle, there are usually exceptions.