Problem with Fourtrax 300

[redrider420]

My friend owns an old Fourtrax 300. I don't know what year it is, but it smokes really bad. Does anyone know what the problem could be? My friend said that the owner before him got sand or something in the motor but i'm sure that one of them got it out. Could that be the problem? Thanks

[killed300ex]

what color is trhe smoke? Could either be running rich or need a top end rebuild
killed

[phatswinn]

if its blue u need to do a top end rebiuld cuz therings are shot