can someone give me a rundown on the procedure for replacing the wear buttons in the secondary clutch on a 02 mxz800??????

Very easy, the button holes actually are all the way through the secondary, just push the old ones out through from the back, they should pop out real easy and push the new ones in.

do i have to take the secondary off or can i do this on the sled???....do i need any special tools(pullers,etc)???

You will need to take the secondary off the sled, and a clutch press would make everything go alot easier. ALso you will need some snap ring pliers.

02 800 has the rer driven so all you have is the half moon clips you pull out when you compress the spring, those drivens are really easy to work on.