My rear shock on my '87 KX80 is really soft. When I sit down on the seat the rear goes down alot and when I go to jump with it it bottom outs unless I land standing on ther pegs. I don't know to much about suspension but what could I do to stiffin the rear shock? It doesn't make any weird noises. Do I just have to tighten the shock spring or does it need to be rebuilt?.....:think