Naturally every bike is different so there can be slight differences. Start by installing the bike into a workshop stand and prepare the tools required. You will need Allan keys, Paper towel, Degreaser and grease
1. Start by loosening the pinch bolts on the stem, then remove the top cap
2. Remove the stem from the fork tube and rest gently
3. Remove the spacers, compression ring and dust seals, making note of the order as you do. you can thread a cable tie through to keep them in order and stop them from getting lost
4. The forks should now slide out, If it doesn't a gentle tap will normally free it
5. Remove the fork, then remove the upper and lower bearings from the cups along with any remaining seals. You can rest the fork in the headtube for the time being.
6. Spray on some degreaser and clean up the bearing cups and the crown race
7. Clean the bearings and any other part that is covered in grease
8. Apply some grease to the bottom bearing race, do not use too much or it will spill onto the frame
9. Take the new bearings, apply a little grease and place on the crown race of the fork. The bearings have a chamfer on both side, the side it the chamfer on the outside is the side that fits into the frame or the headset cup
10. Fit the fork back into the headtube of the bike. then grease and replace the top bearing. Making sure the chamfered outside edge goes into the frame
11. Lift up the fork and hold in place. Return the compression ring and seals onto the top of the bearing
12. Finally replace all the washers and spacers followed by the stem
13. Return the top cap and tighten the bolt until it takes up the slack. Its really easy to over tighten this bolt so ensure you give it minimal force or you can damage the bearings. If the bars feel stiff to turn you have over done it.
14. Take the bike out of the stand and give it a bounce on the ground to ensure everything is seated into place. To make sure the headset is correctly tighten squeeze the front brake and rock the bike back and forth. If you feel any knocking or play it will require further tightening
15. Align the front wheel with the bars by eye then finally tighten the pinch bolts to the correct torque. These bolts work as a pair so make sure they are evenly tightened
16. You are now ready to test ride
To prolong the life of your bearings, do not direct a high jet of water near areas of your bike where bearings are situated - an ingress of water can lead to premature bearing failure.