Motorcycle Steering Head Bearing Adjustment

After riding my new work bike for a few days, I noticed a sloppy chattering coming from the front end when braking. It seemed like a poorly adjusted head bearing, and since I haven’t purchased a manual yet, I turned to the online forums for guidance and maybe to look at some old BMW stuff. To my disappointment, a google search returned almost nothing and I remembered that sport bike douches don’t work on their own bikes. Because of my endless gratitude to some anonymous knee dragger dot com forum poster that helped me through a difficult carburetor tune, I’m posting my repair in hopes that some other joker can figure out what that funny washer between the two castellated nuts does. This head bearing adjustment was performed on a 2005 Kawasaki Ninja ZX-6R.

1. Remove the steering dampener. Mine has an aftermarket dampener attached to the head and the frame at the tank bolts. The dampener has to be removed to get an accurate feel for the bearing adjustment.

2. Remove the top nut.

3. Remove the clamp bolts that clamp the top yoke to the fork tubes. The Ninja also has two bolts on the bottom of the yoke that had to be removed.

4. Remove the top yoke.

5. Here is where other bikes might vary, but the procedure is pretty much the same, I imagine. The bottom nut is the one that actually adjusts the bearing, and another nut will lock against it to prevent it from rotating on the threads of the steering tube. My bike has two castellated nuts with a funny washer between them. The washer has little tabs that bend into the castle-marks of the two nuts, to further prevent either of them from rotating. I had to bend all the little tabs flat in order to unscrew the upper castellated nut.

Then, remove the upper castellated nut.

6. Now it’s time for the actual bearing adjustment. Kawasaki makes a special adjustment tool, but I used a hook-type spanner that I had lying around and it worked OK. Bicycle shops sell a similar spanner. I only tightened the lower nut about a quarter of a turn, which turned out to be about just right. If your bike is way out of adjustment, you may need to repack or replace the head bearings.

Now put it all back together, except for the steering dampener. The dampener needs to be off to get a good feel for the bearing adjustment.

Checking your head bearing adjustment requires a lift that can get the front end of the bike off the ground and let the forks and turn freely. If you don’t have the lift, and you need to ride your bike for work the next day like I did, you can use this technique: have your buddy push the bike so that it pivots on the side stand, while you push up on the front, near the headlight. The bike will be on its rear tire and the side stand, and you will be able to awkwardly grab the fork legs and check for play in the bearing. If the bearing is too tight, the forks and wheel will have a hard time “falling” under the weight of the wheel when you let go of it (the wheel.) If you still feel any play in the bearing when you wiggle the fork legs, go back and re-tighten that lower nut a little. If the bearing feels bound up when the wheel falls to the side, back off the nut. Vroom!