At 170 lbs., you will never get the forks to be very good unless you toss the stock .35 springs for some .40's or .41's. They are only about $80 for a set. It is money well spent, and is probably the single best improvement you can do to the KDX. With the stock springs, the forks ride around at half-mast all the time, keeping them down in the firm part of the travel, giving up plushness, and causing deflection and harshness. The stiffer springs will improve the handling tremendously, as the front and rear will be in better balance.