In less than 500 miles of trail riding, mostly sandy loam, the rear wheel bearing is going out again. The play is very little right now, but I know its going to get worse fast. Anyone experience the same problem?

I ride in alot of sand, and I can't say I go through wheel bearings that fast. Mind you I haven't really checked them by removing them, but I am a clean freak when it comes to my bike and make sure to really get in there after every ride. How often do you wash your bike?

The most common killer of rear wheel bearings is improper chain tension.

What he said. Bust out that ruler and measure 55-65mm from where it says, I believe the front kickstand bolt. When properly adjusted and the bike just sitting on the kickstand the kdx chain looks really slack compared to most bikes. This is normal.

Slick_Nick said:

:thumbsup: Yep. The "three-finger-method" is complete bs. Every bike has it's own specific chain adjustment specs as outlined in the manual. Follow them and you can't go wrong. I am amazed at how often I see people with their chains too tight.

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Always remember if you have to choose, too loose is way better than too tight...

I ride in sand, rarely wash the bike and I am not going through wheel bearings. The chain slack on my 2003 KDX200 is a little loose, 75mm, but acceptable.

I would think you have some type of alignment or binding problem. Or as others have said the chain is too tight.

NewMexico505 said:

That's not really "acceptable." The acceptable range is 55-65mm. Tighten that shiz up before you go through sprokets.

What bearings are you buying, and are you popping the shields off and and greasing them when you re-assemble? The bearings usually only have enough grease from the factory to prevent rust in transit. I always pack them full of grease on both sides of the bearing before installing them.

Chokey said:

That is the best post I think I have ever seen on chain tension adjustment. The suggestion for a GO/NO-GO block is a good idea.

Thank you everyone for the responses. I ran out and adjusted my chain tonight. Turns out I had it a bit too tight, specs is shown at 55mm to 65mm taking a measurement perpendicular to the swingarm to the bottom of the chain. I believe before the adustment it was at 50mm-55mm. Now it is correctly adjusted to the manual at 60mm dead nuts. I should add just like Slick_Nick said, the chain does appear to look like it has a lot of slack when adjusted properly.

I don't ussually wash the bike every ride, we ride almost every weekend here so it looks like I'll start washing my bike after every ride.

As far as the bearings are concerned, I don't have a bike shop for 50+ miles so I had the bearings measured and got them from Napa. They are Napa's Proformer bearings, at 7 dollars a piece.

GLad you got it figured out!

A quick and good way of testing the chain slack on the KDX,with the bike on a stand,rear wheel off the ground,press down on the top run of the chain,it should just come in contact with the rear most part of the top swingarm slider.
Check with a local seal shop or Napa and see if you can purchase the rear seals in Double Lipped,ID and OD are the same measurements but width will be wider,7mm I think they were,but there is more than enough room for them,they stick out slightly more from the hub but they will greatly increase bearing life.