I pulled my four wheeler in the shed and changed the oil then when i backed it out smoke was every where. A few days later i changed the oil again and i could smell gas in the oil and it still smokes. Where do i need to start replacing parts?

 

Without knowing anything else about the bikes previous record.......
was the bike smoking before you changed the oil?
did you over fill with oil on the first change?
why did you change the oil again the second time?
did you smell gas before the first change.?
was the bike jacked up for hours with the gas on ?
have you looked at the air box to see if there is gas in the air box?

most of the time if the fuel shut off is left on and the needle and seat are leaking they can put gas in the air box or in worse case situation gas in the crankcase where the oil goes..
this will raise the oil level and thin the oil out with gas... both can cause smoking problems.

Keep us informed on your situation.