Hello, newbie, introduction, need help

Welcome, Glad to have you onboard.

The front is pretty much straight forward as you can use standard Yamaha parts. Look at some of the larger Yamaha's from the same time period and back for calipers and discs.

Rear is a little harder to do if you really want a disc. Something will have to be adapted from a modern dual purpose bike like a DRZ Suzuki.

Have fun!. These bikes are a blast to ride and to mod.