I have 2003 450 foreman rebuilt top end on bike about a year ago, bike runs fine got a little water in the motor about 6 months ago and it just started smoking but it only smokes when its cold once it warms up it stops, could it be something with the valves? any ideas?

 

Water often comes with some grit in it, which could have toasted your rings.

Did you get water in your crankcase, and neglect to deal with the contaminated oil?