The 84/85 KXTs had a long rubber chain slider that fit snuggly over the swingarm. It wrapped around the front and came back quite a ways. It protects the top, bottom, and covers the side a little. You can see the top of it in the upper right of the pic I attached.
You might get in touch with
http://www.tmdesignworks.com/
See if they have something that will work, or can make you a nice slider.
1986 Tecate
1984 Tecate
1985 Tri-Z
1986 ATC350X
1985 ATC250R (2)
1985 ATC125M (2)
1982 ATC70 - Original Owner
175 TriMoto Frame with Pro-Tec Rear Suspension
3-Wheelin' since '82