I need to upgrade the front and rear springs on my son's 2002 KX65. We went to the next shorter dogbone to raise the rear end, I've got 15 weight oil in the forks, both the front and rear are set at the firmest settings, and he says he still bottoming out on big jumps.
If I go from 4.9kgf/mm to 5.1 on the rear, what should I go with on the front? 2.8 or 2.9?
Use the Race Tech site to calculate spring rates. You can cut off some of the stock spring to increase spring rate but that is hit or miss.
http://www.racetech.com/homedirt.asp?showPage=dirt