Wrist fatigue is a problem that a lot of bikers suffer from, and many of them may not realize that this pain or pressure is from the way that they ride the motorcycle and grip the handlebars. Also, the constant vibration that travels through the frame of the bike and into the handlebars can cause your hands to grow numb and can cause some aches and tension in your knuckles, wrists, and other joints. There are a few different specialty products that you can do to deal with wrist fatigue.
For example, there are a number of padded gloves that are designed to absorb the shock of the vibrations. Depending on your style and the season in which you are riding, there are a number of options ranging from fingerless gloves to fully padded ones. If you have trouble finding a pair of gloves that might work, check out those available for weightlifters or cycling. If you wanted to make them more specific to biking, you could decorate them with motorcycle patches. If you don't like to wear gloves, you can order specialized after-market handle grips that will put extra padding on your existing grips.
Another option would be to add risers to your handlebars. If you make them a little higher, this can alleviate pressure on your wrists. Finally, if you are someone who really rides a lot and does a lot of long distance biking, then you might consider getting a cruise control system installed. While this might be expensive up front, it could save you from extended problems and wrist difficulties in the future. It would make your ride a lot easier and less demanding on your body.