Here are some good numbers and and excellent write up I got from http://www.lsracing.com/installguides.php?step=4&igid=5
CASTER & CAMBER TUTORIAL POSTED: 2002-06-03
CAMBER
Camber is the amount of degrees that the tire and wheel is tilted in or out at the top in relation to the bottom of the tire. A tire that is tilted in at the top and out at the bottom is said to have negative camber. The farther it angles out at the bottom the greater the amount of negative camber.
For positive camber, the top of the tire is farther out than the bottom. The reason for having camber in your front end is as follows. An ATV's suspension is forced over in a corner and the suspension flexes. With everything in motion, all this force wants to flex the tire more upright, or reducing the amount of negative camber.
A tire's greatest traction is achieved when more of the tread is in contact with the ground. As the bike enters a corner, the forces tend to bend everything over, adding positive camber. To make sure that the tire's greatest amount of tread is in full contact when it is most needed, we set up the front suspension with a negative camber. How much negative camber you choose depends on the amount of suspension travel, and some various other factors such as the terrain you plan to ride on.
Recommended Camber: Negative
Motocross: 4.5