Bottom Shock Bearing Replacement

[Rick]

Of all the suspension bearings on the Kawasaki, the bottom shock bearing is the one I change more than any others, probably two times a year on average.  On older bikes, the bottom shock bearing was a heim joint, which I have always believed was better than needle bearings, but Kawasaki didn't ask me before changing.  Go figure...

Changing the bottom shock bearing on any Kawasaki is rather simple and on the KX500, only requires removal of the shock.  On other models, I believe you can perform this by shock removal only as long as you support the rear wheel on some type of block to expose the bearing below the dog bones.  I'll be changing the shock bearing on the KX125 tonight, so will test the theory then.

You will need the following to build a little bearing press:

1. 7/8 inch 1/2 drive socket (I think a 22mm will work also)
2. 9/16 inch 3/8 drive socket (a 14mm should work here, but hold up to the bearing and make sure the socket is a little smaller than the bearing.  Same goes for the 9/16 socket, as different manufacturers will have different wall thicknesses.  If your socket is bigger than the bearing, try the next size down or a different brand socket.)
3. 3/8 x 6 inch bolt with threads all the way to the head.
4. 3/8 nut
5. Two 3/8 washers
6. New bearing

The steps to removal after the bearing pin and seals have been removed from the bearing:

1. Place one washer on the bolt.
2. Place the 7/8 socket on the bolt with the open end facing away from the head of the bolt.
3. Thread the bolt through the bearing.
4. Place the 9/16 socket on the bolt with the open end facing away from the head of the bolt.
5. Place the second washer on the bolt, and the nut.
6. Begin to tighten the nut on the bolt, and the bearing will be pushed into the 7/8 socket.

Installation of the new bearing:

1. Follow steps 1, 2, & 3 above, but put a little grease inside the bearing pocket before you begin.
2. Thread the new bearing on the bolt.
3. Put washer and nut on bolt, and tighten.  This will push the bearing almost all the way in place.
4. Remove the washer and nut and install the 9/16 socket and then the washer and nut.  Tighten the nut and you will press the bearing in the last 1/8 inch to allow the seals to be install on both sides.

Simple cheap bearing press that does the trick with very little disassembly.

Rick

[kawdude]

Does the bottom bearing have the most pressure asserted on it to cause it to wear faster or it because of the location of the bearing...ie mud, water, sludge.

[Rick]

In my oppinion, it is a little of both.  

If you think about the operation of the shock as the swingarm goes through the arc, the bearing does not really have much rotation.  The bigger issue is that the bearing takes the brunt of the impact as the shock is compressed.  No other bearing on the rear suspension takes as much abuse as the shock bearings.  Couple this abuse with the fact that it is the lowest bearing on the bike and gets dragged through mud, water, snow, etc., and has rather poor bearing seals, it's easy to see why this particular bearing is prone to failure.

Fortunately, the bearing is cheap (I think it retails for less than $10), and is easy to change, so does not present a big issue.  However, I have seen this bearing neglected before, and the result was the bearing pin wore through the destroyed bearing, and into the aluminum pocket.  That 10 bucks looked pretty cheap compared to the price tag of the replacement suspension parts.

Rick

[bigborefan]

I think one of the big prblems with this bearing is that the carb overflow tubes wash out the grease. I keep a spare in my tool box at all times. Also try and grease it after every ride, just takes a few minutes.