Wilsons Sandbox

I am planning to change out the fork oil in hopes that will improve the front suspension. Anyone that has done this, your advise would be much appriciated. I have a 99 KLR650 and think that the forks have drain holes near the bottom of the fork tubes. I am hoping to just drain out the old oil then open up the tops and fill up with new heavier weight fork oil. What weight is best to use? Thanks John Sterling, VA 99 KLR 650