If the oil is still milky, keep changing it until you get dark, clean oil coming out. What we used to do with airplanes was use a oil drum and pump, but not sure that would work here. Just keep changing until it's not milky any more. Then you should drive it for awhile and check it again. If it's still not milky, it's good to go.
2007 Foreman TRX500 manual shift
27" Super Swamper Vampires
K&N air filter
Hopefully more mods to come...