Its a bit diferent hauling on the grab bar, as opposed to just having it sit in the garage.
Make sure you take out the battery, all the jiggling around and bouncing, could shake all the crap at the bottom of the battery case, and now send it to the side.
If the gas level is low enough, it shouldnt come out the cap vent, but if its posible..drain the tank and float bowl, and refill when you get there.

 

Well I hauled mine in a back of a nissan with DS 650.. I had my 400EX on end almost on the bar with the front tires over the cab, with the frame resting on the cab,,(ouch the cab got dented) and the DS right up against my rear tires.. I had my rear fenders off.

I and a friend drove it this way from Seattle to Arizona. I turned the gas off and that was it.. But before starting it I let it sit for a while, and I cranked the engine over before starting it.
It was wild to see that in a back of a old Nissan pick up.