Top Steering Head Bearings

[CaptainKnobby]

On the last three bikes I have bought new (2006,2010,2011 YZ450's) I have tried too maintain the steering head bearings. On the 06 I had to replace both due to not greasing them after each year. When I bought new ones for it I kept them greased but the top bearing would still have like burnt spots on some of the rollers and on the race.

When I bought the 2010 model I greased both bearings before I rode it and the top bearing still went bad in a years time. Had the same burnt look on the race and the rollers (like surface rust). When you took the front tire off and the forks off and turned the handle bars you could feel that roughness (notchiness).

When I bought my 2011 model I did the same thing. Took the steering stem out and greased the bearings before riding it. Now at 17.4 hours on it I thought I would check them and sure enough the top one had the same surface rust on the race and the rollers and had that notchiness feel to them.

I just took 800 grit sandpaper and cleaned them up a bit which helped and repacked and put it back in,but could still feel some notching but not as bad.

What grease would be good to use for the top bearing? The bottom ones were fine. I'm useing the Moly disulfied soap base that the manual calls for. I have tried the Red extreme pressure grease before and had good results with it but changed to the Molly. The BellRay water proof marine saltwater grease didnt work either.

[grayracer513]

You probably use a pressure washer, or at least a high pressure nozzle on the garden hose, eh? The problem is water. I assume that this late in the game, whether you asked for them or not, you got the updated top bearing with the seal built into the inner race, but it would seem as if it either isn't as effective as the top seal was on the steel frame, or you're blasting too much water on the steering head too hard. Take it a little easier on that area.

The best grease to use is one rated for boat trailer wheel bearings that get submerged. Look for the word "marine" and/or "waterproof" in the labeling. Moly is good to have, but not at the expense of water resistance. Another point is that there's a difference between a grease that will resist being washed out by water and one that will keep water away from the bearings.

[CaptainKnobby]

I only use a garden hose to wash it and the nozzle I have for it has different settings. I use the "jet" setting but avoid spraying water around the steering stem and the handle bars at full speed,I just spray about 1/4 to half throttle. I have the Fleex handle bars on my bike so that is another reason to not spray hard at these areas.

There was a couple times i used a pressure washer at the track but stayed away from the steering head and handle bars about two feet and the setting for washing was low. I mean the pressure washer was running just enough to keep it running when you pulled the trigger.

The top bearing in my steering stem wasn't the sealed type. it was the same as all the others in my 06 and 2010. I had the same problem when I used the Bel-Ray grease that was supposed to be water proof.

However I will try and find some boat/trailer bearing wheel grease labeled waterproof.

I will also try to avoid useing any water around the steering head.

[grayracer513]

Replace the bearing with PN 93332-00078-00.

93332-00068-00 is the old one.