Adjust Shimano Dura Ace 9000 Hubs:
Before getting specifically into Shimano Dura Ace Hubs, it is important to understand how to adjust a typical cup or cone hub. With this hub, you have a threaded axel with a cup/cone and locknut to hold it in place. To adjust the cone, you first need to loosen the locknut. Use a cone wrench to hold the cone and an open end wrench to loosen the locknut. Then, very lightly tighten down the cone until you feel it contact the ball bearings. Tighten down the locknut by hand onto the cone.
If done right, the axel will feel a little rough at this point. Now, use your cone wrench to tighten the cone down against the locknut. It should be tight, but this doesn’t require strenuous effort to tighten. If the axel rattles, use two open end wrenches to tighten down both locknuts just a tiny bit to get to where you need to be. If the axel turns roughly, use two cone wrenches to back off the cones slightly. If either of these adjustments takes more than a tenth of a turn, start over and get your cones in a better position.
For Dura Ace 9000 hubs, adjustment is straight forward. Both the front and rear, use the same process for adjustment. Use two 5mm allen keys inserted into each end of the axel to unscrew the non-drive side end cap bolt. Pull the other end cap off to expose the cone adjustment. Turn it by hand until the axel is rattle free, then put the black cap back on the axel to lock down the adjustment. Line up the wrench flats on the axel with the flat edge of the keyway on the adjuster cap. Because small splines on the inside of the cap lock the adjuster in place, you can tighten the axel end cap bolt, which serves as the axel locknut, with two 5mm allen wrenches.