Got my son a 2001 KX85. The problem is that nutural is huge. It is hard to get it into 1st, and sometimes to start off, you have to shift to 2nd then down to 1st inorder to get it into gear. When riding, going from 2nd to 1st you almost always hits nutural. Going from 1st to 2nd is not as bad. I changed the oil and it did not help out. So is this a shift fork, or drum? Do I need to split the cases to fix this? Thanks in advance for your help.