Bearing failure in the 8ight has alot to do with gear mesh. It should be set a little looser than most other buggies because the chassis flexes so much. What many people do is use a piece of notebook paper in between the gears to set the mesh correctly. But on the 8ight, I've read that you should double it up to get the mesh a little looser.

Another thing to watch for is to make sure the engine is squared up properly. In other words, make sure the clutchbell isn't engaging the spur at an angle. Make sure the engine is sitting straight in the chassis.