What are the specs for fork oil in a 99 YZ 125

Use a good quality 5Wt suspension oil (or 7Wt if you want more dampening but this will make it a little more stiff through the small stuff). With the springs removed, fill the forks to the top, cycle the damper rod up and down until it has consistant and firm resistance, top the fluid off to the top, lift the outer tube up about 6" then set it back down, top off, then let it sit until you see no more bubbles. Stroke the damper rod again to ensure there is no air and then **** out fluid until your level is between 110 and 150MM in each tube. Make sure each tube is filled to the same level. One quart per fork is enough to do the job but you might need three quarts to have both filled prior to sucking the excess back out. I usually start with three bottles.

For a firmer feel, use more oil (110MM). For a softer feel, use less fluid (150MM). This is measured from the top of each tube to the level of the oil. Just use a piece of clear tubing and an irrigation syringe - you can get one from a local animal vet. Just mark the tubing with a sharpie at the level you desire.

My standard setting was 135MM from the top using 7Wt oil. I am 160lbs and a mid pack A class rider using essentially stock valving with stock springs.