The stripped bolt might be able to be backed out with upwards pressure. Use a screwdriver under the bolt head and pry up while slowly turning the socket. This will be slow as the screwdriver will jump loose about every 1/4 turn.
eat it
Try purchasing "Bolt-Out", made by Craftsman, available at Sears. GEts wonderful reviews for removing stripped bolts!
drill it out with a power drill
turn a tool
Use an easy-out of harder metal after drilling a small hole with harder metal.
On an '89, remove both side covers and you will see a bolt on both sides of the bike just under the seat. Remove the bolts, lift the back of the seat and slide toward the rear of the bike.
Purchase the appropriate sized easy out and drill bit from an auto parts store and drill into the center of the bolt head, you then insert the easy out and its reverse threads will back the bolt out. ( as you tighten the easy out counterclockwise the bolt will loosen )
helicoil
Start bike and allow it to warm up. There is a large drain bolt beneath the engine crankcase. Remove the drain bolt and the oil will evacuate the crankcases. Reinstall the drain bolt. Remove the oil filter located on the front of the engine cases. Install a new filter. Bike will hold 3 quarts when changed with the filter.
Stripped bolts can be repaired by a knowledgeable person using Heli-coils.
If you mean the head of the bolt is stripped, there is a tool called a back out. You employ it by drilling the right size hole in the top of the bolt, inserting the backout. The backout, when turned, will grip the bolt inside the hole sufficiently to turn it. Also drilling a hole through the bold will take the pressue off the threads of the bolt and with a paid of vice grips you may be able to turn it. I'd try the backout, it's nearly fool proof.
Drill it buy new hex nut. If unable to find new hex nut. Buy new ...