You guys are a little mixed up with your terms i think.

Caster is that angle of the steering pivot relative to the ground, looked at from the side of the car. When the car is moving forward, the wheels want to follow the steering pivot (like in a shopping cart wheel) This creates straight line stability. It also adds camber as the wheel is turned. (which is usually good)

Dockman, i think you are talking about camber, which is the angle that the tires make relative to vertical, looking from the front or the back of the car. Like you said, it is there to maximize the tires' contact with the ground while body rolls in the turn.

As far as i know mittimj, there is no good reason to make one of your tires lift during a turn, it would mean less traction and poor cornering. In your go-kart, caster doesn't likely cause the wheel lift. It's probably just a consequence of a solid axle, and no springs or dampers. It's likely unavoidable as soon as the body rolls enough in a turn.

[link=http://www.ozebiz.com.au/racetech/theory/align.html]Here's[/link] a decent but not too technical read about caster, camber and toe.