Bottom Line Up Front: I'm thinkin' that a high quality polyurea-based grease rated for EP applications is the best to use for motorcycle steering head bearings.
As seen in
this thread (page 28), I recently repacked the steering head bearings in a 2007 Kawasaki KLR 650 that had only 1200 (rain-free) miles on it.
The factory grease job:
Note the unusual color of the OEM grease (sort of a babysh*t green). More on this below.
My intention was to pack the steering stem bearings with a high quality grease of some type. Now, I've got four different kinds of bikes and a factory service manual (FSM) for each of the four different types. Three out of the four FSM's don't really stipulate a special kind of grease for the steering head bearings. The FSM for my '05 Gold Wing, however, states that an extreme pressure (EP) rated polyurea-based grease be used. Some Internet research yielded that these types of greases seemed to be highly regarded for this application.
Now, I know that the most common grease to use in this application is probably Bel-Ray Waterproof grease. That is what I've used in the past, anyway. However, some research indicated that Bel-Ray makes no claims of EP qualities for that grease. Note that Bel-Ray DOES sell something similar, with EP qualities (
Marine Extreme Pressure Waterproof Grease), but I was intrigued with finding out more about the grease that Honda recommended for my '05 Gold Wing.
The Honda FSM for my Gold Wing specifically points out two brands of grease that fit the bill for the bike's steering head bearings and the associated dust seal lips. Of those two, “Shell Stamina EP2” looked to be the most accessible to me (the other grease that was mentioned was “Excelight EP2”, manufactured by Kyodo Yushi Japan). It turns out that the Shell grease (an abbreviated set of specs can be found
here) has since been replaced by “Shell Gadus S3 T 220 2” (on which the specs can be found
here).
Well, I couldn't source any of the Shell grease locally, so back on the Internet I went. I found some Mobil grease locally,
“Mobil Polyrex EP2,”, that seemed to match up nicely with the hard to find Shell Gadus grease. Since it was priced reasonably, (less than $10.00 for a 14 oz. cartridge), I tooted over and got me one of 'em.
Imagine my surprise when I popped the top off of the new grease and found it to be about the same color of the OEM grease I'd found on the steering stem bearings! One wonders if Kawasaki is using this stuff at the factory for this application (it is worth noting, however, that the Kawasaki FSM for the KLR650 does
not specify any special kind of grease for the steering head bearings....).
On a side note, when I was later trying to figure out how to clean the lower steering stem bearing (which was press fit onto the steering stem/lower triple clamp assy) without damaging the captive black rubber grease seal, I came across the suggestion of using transmission fluid to do the job. I have lots of this stuff on hand, purchased for a car I no longer own, and saw this as a good way to get rid of some of that stash. However, when testing a bit of the old, OEM grease, I found that it would not readily dissolve in the tranny fluid. Curiosity fully aroused, I tried the same trick with a bit of the new Mobil grease I'd just purchased (see above). Same result. I then tried to dissolve a bit of lithium-based grease in the tranny fluid and found that it dissolved rather easily. One could be forgiven for thus jumping to the conclusion that the factory used polyurea-based grease to pack the steering stem bearings.
So, Honda recommends this grease for the 2005 GL1800 and Kawasaki seemed to be using it on their 2007 KLR 650's.
Until I'm convinced otherwise, I'll use the Mobil Polyrex EP2 grease on all of my steering head bearings from here on out....
If you can't find it locally, note that I've seen it being sold on eBay from time to time.
Pages: 1
