alright what do I need to do to my 2000 foreman 450 s, when I first start it up it smokes like a mother , but after it warms up it only smokes every once in a little while, seems like only when i rev it up and let off it quickly. Someone told me that it was something to do with the valve seals, is this correct? Also another quick question how hard is it to change to front wheel bearings on the same wheler.