How can I build a 4 wheeled device on which a harley sportster can be loaded and transported?

The device would be operated by one or more 12v dc motors.  Power for the motors will be obtained from a pickup truck battery.
I want to use the device to load a harley sportster, which weighs 500 lbs., onto the box of a pickup truck.   Loading will be enabled by a platform, angled from ground surface to truck box. 

Presently, I'm able to use a 12v winch, attached to the front end of the truck box,  to pull the bike up a ramp onto the truck box. To hold the bike erect while it is being pulled up the ramp, I use two 8 inch air filled wheels attached to the bike,( by a very makeshift wooden settup) one wheel on each side of the bike.  However, the bike must be pulled backwards onto the truck box so that it can be more safely offloaded by riding the bike, in its forward position, off the truck and down the ramp .   In order to keep the front wheel straight, this method still requires more than one person to hold the bike while it is being loaded.  The bike's transmission must be in neutral, but the back wheel, drive belt and xmission gears still turn and provide some resistance. 

A 4 wheeled device loaded with a motorcycle, and operated by seperate electric motors would have free turning wheels and could be used to move the motorcycle around without its need to be pushed manually.  Perhaps it could be controlled remotely. 

lizzyastro7 years ago
I'd build a frame to hang the bike from, with wheels, it'd be more stable
Sorry,
goofed on one of the links'
http://www.tkloader.com/